[crumbs22] Week 06 solutions

container-with-most-water/crumbs22.cpp

@@ -0,0 +1,28 @@
+#include <vector>
+#include <iostream>
+#include <algorithm>
+
+using namespace std;
+
+class Solution {
+	public:
+		int maxArea(vector<int>& height) {
+			int left = 0;
+			int right = height.size() - 1;
+			int maxArea = 0;
+
+			while (left < right) {
+
+				int area = (right - left) * std::min(height[left], height[right]);
+				if (area > maxArea)
+					maxArea = area;
+
+				if (height[left] < height[right])
+					left++;
+				else
+					right--;
+
+			}
+			return (maxArea);
+		}
+	};

design-add-and-search-words-data-structure/crumbs22.cpp

@@ -0,0 +1,56 @@
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+struct TrieNode {
+	bool isEnd;
+	TrieNode* children[26];
+	TrieNode() : isEnd(false) {
+		for (int i = 0; i < 26; i++)
+			children[i] = nullptr;
+	}
+};
+
+class WordDictionary {
+private:
+	TrieNode* root;
+	bool dfs(string& word, int idx, TrieNode* node) {
+		if (!node)
+			return (false);
+		if (idx == word.size()) // 단어가 끝났을 때만 true
+			return (node->isEnd);
+
+		char c = word[idx];
+		if (c == '.') {
+			for (int i = 0; i < 26; i++) {
+				if (dfs(word, idx + 1, node->children[i]))
+					return (true);
+			}
+			return (false);
+		}
+		else {
+			return dfs(word, idx + 1, node->children[c - 'a']);
+		}
+	}
+
+public:
+    WordDictionary() {
+        root = new TrieNode();
+    }
+
+    void addWord(string word) {
+		TrieNode* cur = root;
+		for (char c : word) {
+			int index = c - 'a';
+			if (!cur->children[index])
+				cur->children[index] = new TrieNode();
+			cur = cur->children[index];
+		}
+		cur->isEnd = true;
+    }
+
+    bool search(string word) {
+        return dfs(word, 0, root);
+    }
+};

longest-increasing-subsequence/crumbs22.cpp

@@ -0,0 +1,22 @@
+#include <iostream>
+#include <vector>
+#include <cmath>
+
+using namespace std;
+
+class Solution {
+	public:
+		int lengthOfLIS(vector<int>& nums) {
+			vector<int> dp(nums.size(), 1);
+			int ans = 1;
+
+			for (int i = 1; i < nums.size(); i++) {
+				for (int j = 0; j < i; j++) {
+					if (nums[i] > nums[j])
+						dp[i] = max(dp[i], dp[j] + 1);
+					ans = max(ans, dp[i]);
+				}
+			}
+			return (ans);
+		}
+	};

valid-parentheses/crumbs22.cpp

@@ -0,0 +1,40 @@
+#include <iostream>
+#include <stack>
+#include <string>
+
+using namespace std;
+
+class Solution {
+	public:
+		bool isValid(string s) {
+			stack<char> st;
+
+			for (char c : s) {
+                // if (!st.empty())
+                //     cout << st.top();
+				if (c == '}') {
+					if (st.empty() || st.top() != '{') {
+						return (false);
+					}
+					st.pop();
+                    continue ;
+				}
+				else if (c == ')') {
+					if (st.empty() || st.top() != '(') {
+						return (false);
+					}
+					st.pop();
+                    continue ;
+				}
+				else if (c == ']') {
+					if (st.empty() || st.top() != '[') {
+						return (false);
+					}
+					st.pop();
+                    continue ;
+				}
+				st.push(c);
+			}
+			return (st.empty());
+		}
+	};