diff --git a/lcci/01.01.Is Unique/README.md b/lcci/01.01.Is Unique/README.md index e8f0aafbf7165..013967f04e16f 100644 --- a/lcci/01.01.Is Unique/README.md +++ b/lcci/01.01.Is Unique/README.md @@ -19,7 +19,7 @@ edit_url: https://github.com/doocs/leetcode/edit/main/lcci/01.01.Is%20Unique/REA

示例 1：

输入: s = "leetcode"
-输出: false 
+输出: false

示例 2：

@@ -56,8 +56,7 @@ edit_url: https://github.com/doocs/leetcode/edit/main/lcci/01.01.Is%20Unique/REA class Solution: def isUnique(self, astr: str) -> bool: mask = 0 - for c in astr: - i = ord(c) - ord('a') + for i in map(lambda c: ord(c) - ord("a"), astr): if (mask >> i) & 1: return False mask |= 1 << i diff --git a/lcci/01.01.Is Unique/README_EN.md b/lcci/01.01.Is Unique/README_EN.md index 86501a1e6e8e5..a63cf58656329 100644 --- a/lcci/01.01.Is Unique/README_EN.md +++ b/lcci/01.01.Is Unique/README_EN.md @@ -64,8 +64,7 @@ The time complexity is $O(n)$, where $n$ is the length of the string. The space class Solution: def isUnique(self, astr: str) -> bool: mask = 0 - for c in astr: - i = ord(c) - ord('a') + for i in map(lambda c: ord(c) - ord("a"), astr): if (mask >> i) & 1: return False mask |= 1 << i diff --git a/lcci/01.01.Is Unique/Solution.py b/lcci/01.01.Is Unique/Solution.py index 1d63247d2b3a0..06482062b2939 100644 --- a/lcci/01.01.Is Unique/Solution.py +++ b/lcci/01.01.Is Unique/Solution.py @@ -1,8 +1,7 @@ class Solution: def isUnique(self, astr: str) -> bool: mask = 0 - for c in astr: - i = ord(c) - ord('a') + for i in map(lambda c: ord(c) - ord("a"), astr): if (mask >> i) & 1: return False mask |= 1 << i diff --git a/lcci/01.02.Check Permutation/README.md b/lcci/01.02.Check Permutation/README.md index db958faa9953e..786b5c7538b57 100644 --- a/lcci/01.02.Check Permutation/README.md +++ b/lcci/01.02.Check Permutation/README.md @@ -93,11 +93,18 @@ class Solution { class Solution { public: bool CheckPermutation(string s1, string s2) { - if (s1.size() != s2.size()) return false; - int cnt[26] = {0}; - for (char& c : s1) ++cnt[c - 'a']; - for (char& c : s2) - if (--cnt[c - 'a'] < 0) return false; + if (s1.size() != s2.size()) { + return false; + } + int cnt[26]{}; + for (char c : s1) { + ++cnt[c - 'a']; + } + for (char c : s2) { + if (--cnt[c - 'a'] < 0) { + return false; + } + } return true; } }; @@ -115,8 +122,7 @@ func CheckPermutation(s1 string, s2 string) bool { cnt[c-'a']++ } for _, c := range s2 { - cnt[c-'a']-- - if cnt[c-'a'] < 0 { + if cnt[c-'a']--; cnt[c-'a'] < 0 { return false } } @@ -128,20 +134,18 @@ func CheckPermutation(s1 string, s2 string) bool { ```ts function CheckPermutation(s1: string, s2: string): boolean { - const n = s1.length; - const m = s2.length; - if (n !== m) { + if (s1.length !== s2.length) { return false; } - const map = new Map(); - for (let i = 0; i < n; i++) { - map.set(s1[i], (map.get(s1[i]) ?? 0) + 1); - map.set(s2[i], (map.get(s2[i]) ?? 0) - 1); + const cnt: Record = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (const v of map.values()) { - if (v !== 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; } @@ -150,22 +154,26 @@ function CheckPermutation(s1: string, s2: string): boolean { #### Rust ```rust -use std::collections::HashMap; impl Solution { pub fn check_permutation(s1: String, s2: String) -> bool { - let n = s1.len(); - let m = s2.len(); - if n != m { + if s1.len() != s2.len() { return false; } - let s1 = s1.as_bytes(); - let s2 = s2.as_bytes(); - let mut map = HashMap::new(); - for i in 0..n { - *map.entry(s1[i]).or_insert(0) += 1; - *map.entry(s2[i]).or_insert(0) -= 1; + + let mut cnt = vec![0; 26]; + for c in s1.chars() { + cnt[(c as usize - 'a' as usize)] += 1; + } + + for c in s2.chars() { + let index = c as usize - 'a' as usize; + if cnt[index] == 0 { + return false; + } + cnt[index] -= 1; } - map.values().all(|i| *i == 0) + + true } } ``` @@ -179,19 +187,18 @@ impl Solution { * @return {boolean} */ var CheckPermutation = function (s1, s2) { - if (s1.length != s2.length) { + if (s1.length !== s2.length) { return false; } - const cnt = new Array(26).fill(0); - for (let i = 0; i < s1.length; ++i) { - const j = s1.codePointAt(i) - 'a'.codePointAt(0); - ++cnt[j]; + const cnt = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (let i = 0; i < s2.length; ++i) { - const j = s2.codePointAt(i) - 'a'.codePointAt(0); - if (--cnt[j] < 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; }; @@ -206,19 +213,18 @@ class Solution { return false } - var cnt = Array(repeating: 0, count: 26) + var cnt = [Int](repeating: 0, count: 26) for char in s1 { - let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] += 1 + cnt[Int(char.asciiValue! - Character("a").asciiValue!)] += 1 } for char in s2 { let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] -= 1 - if cnt[index] < 0 { + if cnt[index] == 0 { return false } + cnt[index] -= 1 } return true @@ -268,8 +274,8 @@ class Solution { class Solution { public: bool CheckPermutation(string s1, string s2) { - sort(s1.begin(), s1.end()); - sort(s2.begin(), s2.end()); + ranges::sort(s1); + ranges::sort(s2); return s1 == s2; } }; @@ -308,6 +314,31 @@ impl Solution { } ``` +#### JavaScript + +```js +/** + * @param {string} s1 + * @param {string} s2 + * @return {boolean} + */ +var CheckPermutation = function (s1, s2) { + return [...s1].sort().join('') === [...s2].sort().join(''); +}; +``` + +#### Swift + +```swift +class Solution { + func CheckPermutation(_ s1: String, _ s2: String) -> Bool { + let s1 = s1.sorted() + let s2 = s2.sorted() + return s1 == s2 + } +} +``` + diff --git a/lcci/01.02.Check Permutation/README_EN.md b/lcci/01.02.Check Permutation/README_EN.md index c18cd58477e8d..c582f9a548145 100644 --- a/lcci/01.02.Check Permutation/README_EN.md +++ b/lcci/01.02.Check Permutation/README_EN.md @@ -100,11 +100,18 @@ class Solution { class Solution { public: bool CheckPermutation(string s1, string s2) { - if (s1.size() != s2.size()) return false; - int cnt[26] = {0}; - for (char& c : s1) ++cnt[c - 'a']; - for (char& c : s2) - if (--cnt[c - 'a'] < 0) return false; + if (s1.size() != s2.size()) { + return false; + } + int cnt[26]{}; + for (char c : s1) { + ++cnt[c - 'a']; + } + for (char c : s2) { + if (--cnt[c - 'a'] < 0) { + return false; + } + } return true; } }; @@ -122,8 +129,7 @@ func CheckPermutation(s1 string, s2 string) bool { cnt[c-'a']++ } for _, c := range s2 { - cnt[c-'a']-- - if cnt[c-'a'] < 0 { + if cnt[c-'a']--; cnt[c-'a'] < 0 { return false } } @@ -135,20 +141,18 @@ func CheckPermutation(s1 string, s2 string) bool { ```ts function CheckPermutation(s1: string, s2: string): boolean { - const n = s1.length; - const m = s2.length; - if (n !== m) { + if (s1.length !== s2.length) { return false; } - const map = new Map(); - for (let i = 0; i < n; i++) { - map.set(s1[i], (map.get(s1[i]) ?? 0) + 1); - map.set(s2[i], (map.get(s2[i]) ?? 0) - 1); + const cnt: Record = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (const v of map.values()) { - if (v !== 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; } @@ -157,22 +161,26 @@ function CheckPermutation(s1: string, s2: string): boolean { #### Rust ```rust -use std::collections::HashMap; impl Solution { pub fn check_permutation(s1: String, s2: String) -> bool { - let n = s1.len(); - let m = s2.len(); - if n != m { + if s1.len() != s2.len() { return false; } - let s1 = s1.as_bytes(); - let s2 = s2.as_bytes(); - let mut map = HashMap::new(); - for i in 0..n { - *map.entry(s1[i]).or_insert(0) += 1; - *map.entry(s2[i]).or_insert(0) -= 1; + + let mut cnt = vec![0; 26]; + for c in s1.chars() { + cnt[(c as usize - 'a' as usize)] += 1; + } + + for c in s2.chars() { + let index = c as usize - 'a' as usize; + if cnt[index] == 0 { + return false; + } + cnt[index] -= 1; } - map.values().all(|i| *i == 0) + + true } } ``` @@ -186,19 +194,18 @@ impl Solution { * @return {boolean} */ var CheckPermutation = function (s1, s2) { - if (s1.length != s2.length) { + if (s1.length !== s2.length) { return false; } - const cnt = new Array(26).fill(0); - for (let i = 0; i < s1.length; ++i) { - const j = s1.codePointAt(i) - 'a'.codePointAt(0); - ++cnt[j]; + const cnt = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (let i = 0; i < s2.length; ++i) { - const j = s2.codePointAt(i) - 'a'.codePointAt(0); - if (--cnt[j] < 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; }; @@ -213,19 +220,18 @@ class Solution { return false } - var cnt = Array(repeating: 0, count: 26) + var cnt = [Int](repeating: 0, count: 26) for char in s1 { - let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] += 1 + cnt[Int(char.asciiValue! - Character("a").asciiValue!)] += 1 } for char in s2 { let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] -= 1 - if cnt[index] < 0 { + if cnt[index] == 0 { return false } + cnt[index] -= 1 } return true @@ -275,8 +281,8 @@ class Solution { class Solution { public: bool CheckPermutation(string s1, string s2) { - sort(s1.begin(), s1.end()); - sort(s2.begin(), s2.end()); + ranges::sort(s1); + ranges::sort(s2); return s1 == s2; } }; @@ -315,6 +321,31 @@ impl Solution { } ``` +#### JavaScript + +```js +/** + * @param {string} s1 + * @param {string} s2 + * @return {boolean} + */ +var CheckPermutation = function (s1, s2) { + return [...s1].sort().join('') === [...s2].sort().join(''); +}; +``` + +#### Swift + +```swift +class Solution { + func CheckPermutation(_ s1: String, _ s2: String) -> Bool { + let s1 = s1.sorted() + let s2 = s2.sorted() + return s1 == s2 + } +} +``` + diff --git a/lcci/01.02.Check Permutation/Solution.cpp b/lcci/01.02.Check Permutation/Solution.cpp index 72808b7ee740c..ff8e6d531810c 100644 --- a/lcci/01.02.Check Permutation/Solution.cpp +++ b/lcci/01.02.Check Permutation/Solution.cpp @@ -1,11 +1,18 @@ class Solution { public: bool CheckPermutation(string s1, string s2) { - if (s1.size() != s2.size()) return false; - int cnt[26] = {0}; - for (char& c : s1) ++cnt[c - 'a']; - for (char& c : s2) - if (--cnt[c - 'a'] < 0) return false; + if (s1.size() != s2.size()) { + return false; + } + int cnt[26]{}; + for (char c : s1) { + ++cnt[c - 'a']; + } + for (char c : s2) { + if (--cnt[c - 'a'] < 0) { + return false; + } + } return true; } -}; \ No newline at end of file +}; diff --git a/lcci/01.02.Check Permutation/Solution.go b/lcci/01.02.Check Permutation/Solution.go index 7acd2c2c4bc00..e8fd1ace061de 100644 --- a/lcci/01.02.Check Permutation/Solution.go +++ b/lcci/01.02.Check Permutation/Solution.go @@ -7,10 +7,9 @@ func CheckPermutation(s1 string, s2 string) bool { cnt[c-'a']++ } for _, c := range s2 { - cnt[c-'a']-- - if cnt[c-'a'] < 0 { + if cnt[c-'a']--; cnt[c-'a'] < 0 { return false } } return true -} \ No newline at end of file +} diff --git a/lcci/01.02.Check Permutation/Solution.js b/lcci/01.02.Check Permutation/Solution.js index 4c0adedaf125b..7aa0ea9b1d428 100644 --- a/lcci/01.02.Check Permutation/Solution.js +++ b/lcci/01.02.Check Permutation/Solution.js @@ -4,19 +4,18 @@ * @return {boolean} */ var CheckPermutation = function (s1, s2) { - if (s1.length != s2.length) { + if (s1.length !== s2.length) { return false; } - const cnt = new Array(26).fill(0); - for (let i = 0; i < s1.length; ++i) { - const j = s1.codePointAt(i) - 'a'.codePointAt(0); - ++cnt[j]; + const cnt = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (let i = 0; i < s2.length; ++i) { - const j = s2.codePointAt(i) - 'a'.codePointAt(0); - if (--cnt[j] < 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; }; diff --git a/lcci/01.02.Check Permutation/Solution.rs b/lcci/01.02.Check Permutation/Solution.rs index efe963a0130f2..45cda06875452 100644 --- a/lcci/01.02.Check Permutation/Solution.rs +++ b/lcci/01.02.Check Permutation/Solution.rs @@ -1,18 +1,22 @@ -use std::collections::HashMap; impl Solution { pub fn check_permutation(s1: String, s2: String) -> bool { - let n = s1.len(); - let m = s2.len(); - if n != m { + if s1.len() != s2.len() { return false; } - let s1 = s1.as_bytes(); - let s2 = s2.as_bytes(); - let mut map = HashMap::new(); - for i in 0..n { - *map.entry(s1[i]).or_insert(0) += 1; - *map.entry(s2[i]).or_insert(0) -= 1; + + let mut cnt = vec![0; 26]; + for c in s1.chars() { + cnt[(c as usize - 'a' as usize)] += 1; } - map.values().all(|i| *i == 0) + + for c in s2.chars() { + let index = c as usize - 'a' as usize; + if cnt[index] == 0 { + return false; + } + cnt[index] -= 1; + } + + true } } diff --git a/lcci/01.02.Check Permutation/Solution.swift b/lcci/01.02.Check Permutation/Solution.swift index 7161edfad155c..6bfd2af7416a5 100644 --- a/lcci/01.02.Check Permutation/Solution.swift +++ b/lcci/01.02.Check Permutation/Solution.swift @@ -3,22 +3,21 @@ class Solution { if s1.count != s2.count { return false } - - var cnt = Array(repeating: 0, count: 26) - + + var cnt = [Int](repeating: 0, count: 26) + for char in s1 { - let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] += 1 + cnt[Int(char.asciiValue! - Character("a").asciiValue!)] += 1 } - + for char in s2 { let index = Int(char.asciiValue! - Character("a").asciiValue!) - cnt[index] -= 1 - if cnt[index] < 0 { + if cnt[index] == 0 { return false } + cnt[index] -= 1 } - + return true } -} \ No newline at end of file +} diff --git a/lcci/01.02.Check Permutation/Solution.ts b/lcci/01.02.Check Permutation/Solution.ts index 65f0c434d61b9..b6bb1f8822cec 100644 --- a/lcci/01.02.Check Permutation/Solution.ts +++ b/lcci/01.02.Check Permutation/Solution.ts @@ -1,18 +1,16 @@ function CheckPermutation(s1: string, s2: string): boolean { - const n = s1.length; - const m = s2.length; - if (n !== m) { + if (s1.length !== s2.length) { return false; } - const map = new Map(); - for (let i = 0; i < n; i++) { - map.set(s1[i], (map.get(s1[i]) ?? 0) + 1); - map.set(s2[i], (map.get(s2[i]) ?? 0) - 1); + const cnt: Record = {}; + for (const c of s1) { + cnt[c] = (cnt[c] || 0) + 1; } - for (const v of map.values()) { - if (v !== 0) { + for (const c of s2) { + if (!cnt[c]) { return false; } + cnt[c]--; } return true; } diff --git a/lcci/01.02.Check Permutation/Solution2.cpp b/lcci/01.02.Check Permutation/Solution2.cpp index 70c67c68db593..142e3154d5a17 100644 --- a/lcci/01.02.Check Permutation/Solution2.cpp +++ b/lcci/01.02.Check Permutation/Solution2.cpp @@ -1,8 +1,8 @@ class Solution { public: bool CheckPermutation(string s1, string s2) { - sort(s1.begin(), s1.end()); - sort(s2.begin(), s2.end()); + ranges::sort(s1); + ranges::sort(s2); return s1 == s2; } -}; \ No newline at end of file +}; diff --git a/lcci/01.02.Check Permutation/Solution2.js b/lcci/01.02.Check Permutation/Solution2.js new file mode 100644 index 0000000000000..a5d33c913da3a --- /dev/null +++ b/lcci/01.02.Check Permutation/Solution2.js @@ -0,0 +1,8 @@ +/** + * @param {string} s1 + * @param {string} s2 + * @return {boolean} + */ +var CheckPermutation = function (s1, s2) { + return [...s1].sort().join('') === [...s2].sort().join(''); +}; diff --git a/lcci/01.02.Check Permutation/Solution2.swift b/lcci/01.02.Check Permutation/Solution2.swift new file mode 100644 index 0000000000000..0aef38caddbb4 --- /dev/null +++ b/lcci/01.02.Check Permutation/Solution2.swift @@ -0,0 +1,7 @@ +class Solution { + func CheckPermutation(_ s1: String, _ s2: String) -> Bool { + let s1 = s1.sorted() + let s2 = s2.sorted() + return s1 == s2 + } +} diff --git a/lcci/01.04.Palindrome Permutation/README.md b/lcci/01.04.Palindrome Permutation/README.md index 689ccb5841266..b174846e8cd30 100644 --- a/lcci/01.04.Palindrome Permutation/README.md +++ b/lcci/01.04.Palindrome Permutation/README.md @@ -94,18 +94,15 @@ public: ```go func canPermutePalindrome(s string) bool { - vis := map[rune]bool{} - cnt := 0 + cnt := map[rune]int{} for _, c := range s { - if vis[c] { - vis[c] = false - cnt-- - } else { - vis[c] = true - cnt++ - } + cnt[c]++ } - return cnt < 2 + sum := 0 + for _, v := range cnt { + sum += v & 1 + } + return sum < 2 } ``` @@ -113,34 +110,26 @@ func canPermutePalindrome(s string) bool { ```ts function canPermutePalindrome(s: string): boolean { - const set = new Set(); + const cnt: Record = {}; for (const c of s) { - if (set.has(c)) { - set.delete(c); - } else { - set.add(c); - } + cnt[c] = (cnt[c] || 0) + 1; } - return set.size <= 1; + return Object.values(cnt).filter(v => v % 2 === 1).length < 2; } ``` #### Rust ```rust -use std::collections::HashSet; +use std::collections::HashMap; impl Solution { pub fn can_permute_palindrome(s: String) -> bool { - let mut set = HashSet::new(); + let mut cnt = HashMap::new(); for c in s.chars() { - if set.contains(&c) { - set.remove(&c); - } else { - set.insert(c); - } + *cnt.entry(c).or_insert(0) += 1; } - set.len() <= 1 + cnt.values().filter(|&&v| v % 2 == 1).count() < 2 } } ``` @@ -173,7 +162,7 @@ class Solution { ### 方法二：哈希表的另一种实现 -我们用哈希表 $vis$ 存储每个字符是否出现过。若出现过，则从哈希表中删除该字符；否则，将该字符加入哈希表。 +我们用一个哈希表 $\textit{vis}$ 存储每个字符是否出现过。若出现过，则从哈希表中删除该字符；否则，将该字符加入哈希表。 最后判断哈希表中字符的个数是否小于 $2$，若是，则是回文排列。 @@ -231,6 +220,76 @@ public: }; ``` +#### Go + +```go +func canPermutePalindrome(s string) bool { + vis := map[rune]bool{} + for _, c := range s { + if vis[c] { + delete(vis, c) + } else { + vis[c] = true + } + } + return len(vis) < 2 +} +``` + +#### TypeScript + +```ts +function canPermutePalindrome(s: string): boolean { + const vis = new Set(); + for (const c of s) { + if (vis.has(c)) { + vis.delete(c); + } else { + vis.add(c); + } + } + return vis.size < 2; +} +``` + +#### Rust + +```rust +use std::collections::HashSet; + +impl Solution { + pub fn can_permute_palindrome(s: String) -> bool { + let mut vis = HashSet::new(); + for c in s.chars() { + if vis.contains(&c) { + vis.remove(&c); + } else { + vis.insert(c); + } + } + vis.len() < 2 + } +} +``` + +#### Swift + +```swift +class Solution { + func canPermutePalindrome(_ s: String) -> Bool { + var vis = Set() + for c in s { + if vis.contains(c) { + vis.remove(c) + } else { + vis.insert(c) + } + } + return vis.count < 2 + } +} +``` + diff --git a/lcci/01.04.Palindrome Permutation/README_EN.md b/lcci/01.04.Palindrome Permutation/README_EN.md index e942aadc8b522..28d7e6c7c4c02 100644 --- a/lcci/01.04.Palindrome Permutation/README_EN.md +++ b/lcci/01.04.Palindrome Permutation/README_EN.md @@ -92,18 +92,15 @@ public: ```go func canPermutePalindrome(s string) bool { - vis := map[rune]bool{} - cnt := 0 + cnt := map[rune]int{} for _, c := range s { - if vis[c] { - vis[c] = false - cnt-- - } else { - vis[c] = true - cnt++ - } + cnt[c]++ } - return cnt < 2 + sum := 0 + for _, v := range cnt { + sum += v & 1 + } + return sum < 2 } ``` @@ -111,34 +108,26 @@ func canPermutePalindrome(s string) bool { ```ts function canPermutePalindrome(s: string): boolean { - const set = new Set(); + const cnt: Record = {}; for (const c of s) { - if (set.has(c)) { - set.delete(c); - } else { - set.add(c); - } + cnt[c] = (cnt[c] || 0) + 1; } - return set.size <= 1; + return Object.values(cnt).filter(v => v % 2 === 1).length < 2; } ``` #### Rust ```rust -use std::collections::HashSet; +use std::collections::HashMap; impl Solution { pub fn can_permute_palindrome(s: String) -> bool { - let mut set = HashSet::new(); + let mut cnt = HashMap::new(); for c in s.chars() { - if set.contains(&c) { - set.remove(&c); - } else { - set.insert(c); - } + *cnt.entry(c).or_insert(0) += 1; } - set.len() <= 1 + cnt.values().filter(|&&v| v % 2 == 1).count() < 2 } } ``` @@ -229,6 +218,76 @@ public: }; ``` +#### Go + +```go +func canPermutePalindrome(s string) bool { + vis := map[rune]bool{} + for _, c := range s { + if vis[c] { + delete(vis, c) + } else { + vis[c] = true + } + } + return len(vis) < 2 +} +``` + +#### TypeScript + +```ts +function canPermutePalindrome(s: string): boolean { + const vis = new Set(); + for (const c of s) { + if (vis.has(c)) { + vis.delete(c); + } else { + vis.add(c); + } + } + return vis.size < 2; +} +``` + +#### Rust + +```rust +use std::collections::HashSet; + +impl Solution { + pub fn can_permute_palindrome(s: String) -> bool { + let mut vis = HashSet::new(); + for c in s.chars() { + if vis.contains(&c) { + vis.remove(&c); + } else { + vis.insert(c); + } + } + vis.len() < 2 + } +} +``` + +#### Swift + +```swift +class Solution { + func canPermutePalindrome(_ s: String) -> Bool { + var vis = Set() + for c in s { + if vis.contains(c) { + vis.remove(c) + } else { + vis.insert(c) + } + } + return vis.count < 2 + } +} +``` + diff --git a/lcci/01.04.Palindrome Permutation/Solution.go b/lcci/01.04.Palindrome Permutation/Solution.go index 5d156fd33340e..76d5c69a60a52 100644 --- a/lcci/01.04.Palindrome Permutation/Solution.go +++ b/lcci/01.04.Palindrome Permutation/Solution.go @@ -1,14 +1,11 @@ -func canPermutePalindrome(s string) bool { - vis := map[rune]bool{} - cnt := 0 - for _, c := range s { - if vis[c] { - vis[c] = false - cnt-- - } else { - vis[c] = true - cnt++ - } - } - return cnt < 2 -} \ No newline at end of file +func canPermutePalindrome(s string) bool { + cnt := map[rune]int{} + for _, c := range s { + cnt[c]++ + } + sum := 0 + for _, v := range cnt { + sum += v & 1 + } + return sum < 2 +} diff --git a/lcci/01.04.Palindrome Permutation/Solution.rs b/lcci/01.04.Palindrome Permutation/Solution.rs index 0d0e1b07a5e70..895e119d6b604 100644 --- a/lcci/01.04.Palindrome Permutation/Solution.rs +++ b/lcci/01.04.Palindrome Permutation/Solution.rs @@ -1,15 +1,11 @@ -use std::collections::HashSet; +use std::collections::HashMap; impl Solution { pub fn can_permute_palindrome(s: String) -> bool { - let mut set = HashSet::new(); + let mut cnt = HashMap::new(); for c in s.chars() { - if set.contains(&c) { - set.remove(&c); - } else { - set.insert(c); - } + *cnt.entry(c).or_insert(0) += 1; } - set.len() <= 1 + cnt.values().filter(|&&v| v % 2 == 1).count() < 2 } } diff --git a/lcci/01.04.Palindrome Permutation/Solution.ts b/lcci/01.04.Palindrome Permutation/Solution.ts index 7bd7505057358..44ba2bc906e83 100644 --- a/lcci/01.04.Palindrome Permutation/Solution.ts +++ b/lcci/01.04.Palindrome Permutation/Solution.ts @@ -1,11 +1,7 @@ function canPermutePalindrome(s: string): boolean { - const set = new Set(); + const cnt: Record = {}; for (const c of s) { - if (set.has(c)) { - set.delete(c); - } else { - set.add(c); - } + cnt[c] = (cnt[c] || 0) + 1; } - return set.size <= 1; + return Object.values(cnt).filter(v => v % 2 === 1).length < 2; } diff --git a/lcci/01.04.Palindrome Permutation/Solution2.go b/lcci/01.04.Palindrome Permutation/Solution2.go new file mode 100644 index 0000000000000..425935647c9f4 --- /dev/null +++ b/lcci/01.04.Palindrome Permutation/Solution2.go @@ -0,0 +1,11 @@ +func canPermutePalindrome(s string) bool { + vis := map[rune]bool{} + for _, c := range s { + if vis[c] { + delete(vis, c) + } else { + vis[c] = true + } + } + return len(vis) < 2 +} diff --git a/lcci/01.04.Palindrome Permutation/Solution2.rs b/lcci/01.04.Palindrome Permutation/Solution2.rs new file mode 100644 index 0000000000000..5ef83e50f0c4d --- /dev/null +++ b/lcci/01.04.Palindrome Permutation/Solution2.rs @@ -0,0 +1,15 @@ +use std::collections::HashSet; + +impl Solution { + pub fn can_permute_palindrome(s: String) -> bool { + let mut vis = HashSet::new(); + for c in s.chars() { + if vis.contains(&c) { + vis.remove(&c); + } else { + vis.insert(c); + } + } + vis.len() < 2 + } +} diff --git a/lcci/01.04.Palindrome Permutation/Solution2.swift b/lcci/01.04.Palindrome Permutation/Solution2.swift new file mode 100644 index 0000000000000..993dc395a5b33 --- /dev/null +++ b/lcci/01.04.Palindrome Permutation/Solution2.swift @@ -0,0 +1,13 @@ +class Solution { + func canPermutePalindrome(_ s: String) -> Bool { + var vis = Set() + for c in s { + if vis.contains(c) { + vis.remove(c) + } else { + vis.insert(c) + } + } + return vis.count < 2 + } +} diff --git a/lcci/01.04.Palindrome Permutation/Solution2.ts b/lcci/01.04.Palindrome Permutation/Solution2.ts new file mode 100644 index 0000000000000..c72db04c15438 --- /dev/null +++ b/lcci/01.04.Palindrome Permutation/Solution2.ts @@ -0,0 +1,11 @@ +function canPermutePalindrome(s: string): boolean { + const vis = new Set(); + for (const c of s) { + if (vis.has(c)) { + vis.delete(c); + } else { + vis.add(c); + } + } + return vis.size < 2; +}