Leetcode 1. Two Sum (Easy) (java)

Leetcode 1. Two Sum (Easy) (java)

Tag: Array, Hash Table 

Difficulty: Easy

/*1. Two Sum (Easy)Given an array of integers, return indices of the two numbers such that they add up to a specific target.You may assume that each input would have exactly one solution.Example:Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0, 1].UPDATE (2016/2/13):The return format had been changed to zero-based indices. Please read the above updated description carefully.*/public class Solution {public int[] twoSum(int[] nums, int target) {Map<Integer, Integer> mappping = new HashMap<>();for (int i = 0; i < nums.length; i++) {int gap = target - nums[i];if (mappping.containsKey(gap))return new int[] {mappping.get(gap), i};mappping.put(nums[i], i);}throw new IllegalArgumentException("No");}}