【视频讲解】LeetCode 第 1 号问题：两数之和

给定 nums = [2, 7, 11, 15], target = 9

因为 nums[0] + nums[1] = 2 + 7 = 9
所以返回 [0, 1]

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

       return new int[] {-1,-1};
    }
}