[nrudev] WEEK 01 solutions

contains-duplicate/nrudev.ts

@@ -0,0 +1,9 @@
+function containsDuplicate(nums: number[]): boolean {
+  const map = new Map<number, number>();
+
+  for (let i = 0; i < nums.length; i++) {
+    if (map.has(nums[i])) return true;
+    map.set(nums[i], 1);
+  }
+  return false;
+}

longest-consecutive-sequence/nrudev.ts

@@ -0,0 +1,13 @@
+function longestConsecutive(nums: number[]): number {
+  const set = new Set<number>(nums);
+  let result = 0;
+
+  for (const num of set) {
+    if (set.has(num - 1)) continue;
+    let length = 1;
+    while (set.has(num + length)) length++;
+    result = Math.max(length, result);
+  }
+
+  return result;
+}

top-k-frequent-elements/nrudev.ts

@@ -0,0 +1,13 @@
+function topKFrequent(nums: number[], k: number): number[] {
+  const map: Map<number, number> = new Map();
+
+  nums.forEach((val) => {
+    if (map.has(val)) map.set(val, map.get(val)!! + 1);
+    else map.set(val, 1);
+  });
+
+  return Array.from(map)
+    .sort((a, b) => b[1] - a[1])
+    .slice(0, k)
+    .map((item) => item[0]);
+}

two-sum/nrudev.ts

@@ -0,0 +1,13 @@
+function twoSum(nums: number[], target: number): number[] {
+  const result: number[] = [];
+
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        result.push(i, j);
+      }
+    }
+  }
+
+  return result;
+}