1. Two Sum

1. Two Sum

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, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0, 1].

public class Solution {    public int[] twoSum(int[] nums, int target) {        HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();        int[] ret = new int[2];        for(int i=0; i<nums.length; i++) {            if(map.containsKey(nums[i])) {                ret[0] = map.get(nums[i]);                ret[1] = i;            }            else {                map.put(target-nums[i], i);            }        }        return ret;    }}