[Zioq] Week 1

contains-duplicate/Zioq.js

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+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+var containsDuplicate = function(nums) {
+    let dup_set = new Set(); // Initialize Set
+    for (let num of nums) {
+        dup_set.add(num) // Add value into the set (duplicated value will be ignored)
+    }
+
+    if(dup_set.size !== nums.length) {
+        return true
+    }
+    return false
+};
+
+/* 
+    Space Complexity - O(n) - Create a set to store elements
+    Time Complexity - O(n) - Traverse through the array
+*/
+
+
+/* Test code */
+console.log(containsDuplicate([1, 2, 3, 1])); // true
+console.log(containsDuplicate([1, 2, 3, 4])); // false
+console.log(containsDuplicate([1, 1, 1, 3, 3, 4, 3, 2, 4, 2])); // true
+
+

longest-consecutive-sequence/Zioq.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var longestConsecutive = function(nums) {
+    if(nums.length === 0) return 0
+    let set = new Set();
+    for(const n of nums) {
+        set.add(n);
+    }
+    let max = 0;
+    for(let n of set) {
+        if(!set.has(n-1)) {
+            let count = 0;
+            while(set.has(n++)) {
+                count++;
+            }
+            max = Math.max(max, count);
+        }
+    }
+    return max;
+};
+
+/* Test code */
+console.log(longestConsecutive([9,1,4,7,3,-1,0,5,8,-1,6])); // true

top-k-frequent-elements/Zioq.js

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+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number[]}
+ */
+var topKFrequent = function(nums, k) {
+
+	const map = new Map();
+	let arr = []
+
+	nums.forEach( e => {
+		if(map.has(e)) {
+			let current_value = map.get(e)
+			map.set(e, current_value +1)
+		} else {
+			map.set(e, 1)
+		}
+	})
+	const store = [...map.entries()].sort((a,b) => b[1] - a[1])
+	for( let i = 0 ; i < k && i < store.length ; i++ ) {
+		arr.push(store[i][0])
+	}
+	return arr
+
+};
+
+
+/* Test code */
+console.log(topKFrequent([1,1,1,2,2,3],2)); // true
+console.log(topKFrequent([1,2],1)); // true

valid-palindrome/Zioq.js

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+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isPalindrome = function(s) {
+
+    let text = s.replace(/[^0-9a-z]/gi, '');
+    text = text.replace(/\s/g, '').toLowerCase();
+
+    const str_arr = text.split("");
+    if( str_arr % 2 === 1 ) {   
+        return false;
+    }
+
+    let length = str_arr.length - 1 ;
+    for ( const [i, value] of str_arr.entries()) {
+        if( value == str_arr[length -i] ) continue;
+        if(value != str_arr[length - i]) {
+            return false
+        }
+    }
+    return true;
+};
+
+/* 
+    Space Complexity - O(n) - Create a array to store elements
+    Time Complexity - O(n) - Traverse through the array
+*/
+
+/* Test code */
+console.log(isPalindrome("A man, a plan, a canal: Panama")); // true
+console.log(isPalindrome("race a car")); // false
+console.log(isPalindrome(" ")); // true