Contains Duplicate Visualizer & Step-by-Step Algorithm Solution

Detect duplicate elements in an array using an instant-lookup hash set.

Category: arrays | Difficulty: Easy

Tags: Hash Set, Lookup, Frequency

Contains Duplicate

nums
i
1
0
2
1
3
2
1
3
Seen Numbers Map
(Empty Map)
100%
state
num1
Initialization
1/13
Explanation

Starting containsDuplicate function.

Source Code
1function containsDuplicate(nums) {
2 const map = new Map();
3 for (let i = 0; i < nums.length; i++) {
4 if (map.has(nums[i])) {
5 return true;
6 }
7 map.set(nums[i], true);
8 }
9 return false;
10}