leetcode-1

題目：

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].   

代碼：

public int[] twoSum(int[] nums, int target) {              int[] res = new int[2];     HashMap<Integer, Integer> map = new HashMap();     for(int i = 0; i< nums.length; i++){     int valNeed = target - nums[i];     if(map.get(nums[i]) != null){     res[0] = map.get(nums[i]);     res[1] = i;     break;     }     map.put(valNeed, i);     }     return res;     }