217. Contains Duplicate

Problem

Given an array of integers, find if the array contains any duplicates.

Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.

Example 1:

Input: [1,2,3,1]
Output: true

Example 2:

Input: [1,2,3,4]
Output: false

Example 3:

Input: [1,1,1,3,3,4,3,2,4,2]
Output: true

Summary

This is an easy problem. If the array contains duplicate numbers, output true; otherwise, output false.

Solution Approach

Use a map to determine this.

Code

package leetcode

func containsDuplicate(nums []int) bool {
	record := make(map[int]bool, len(nums))
	for _, n := range nums {
		if _, found := record[n]; found {
			return true
		}
		record[n] = true
	}
	return false
}