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]. Solution：

1 public class Solution { 2     public int[] twoSum(int[] nums, int target) { 3         int i,j; 4         int[] res = new int[]{0,1}; 5         for(i=0;i