leetCode之 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.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

Solution:

public class Solution {
public int[] twoSum(int[] nums, int target) {
if(null == nums || nums.length < 2 ) {
return null;
}
int[] array = new int[2];
Map<Integer,Integer> map = new HashMap<Integer,Integer>();
for(int i=0;i<nums.length;i++) {
map.put(nums[i], i);
}
for(int i=0;i<nums.length;i++) {
int temp = target - nums[i];
if(null != map.get(temp) && map.get(temp) != i) {
array[0] = i;
array[1] = map.get(temp);
}
}
return array;
}
}