contains duplicate solution 1

Author: hyejj19

contains-duplicate/hyejj19.ts

@@ -0,0 +1,12 @@
+function containsDuplicate(nums: number[]): boolean {
+  const numsMap = new Map();
+  nums.forEach(n => {
+    numsMap.set(n, (numsMap.get(n) || 0) + 1);
+  });
+
+  for (const [_, count] of numsMap) {
+    if (count >= 2) return true;
+  }
+
+  return false;
+}