力扣第一题（两数之和）
class Solution { public int[] twoSum(int[] nums, int target) { HashMap<Integer, Integer> hashMap = new HashMap<>(); for (int i = 0; i < nums.length; i++) { int tmp = target - nums[i];// if (hashMap.containsKey(tmp)){ int[] result={i,hashMap.get(tmp)}; return result; } hashMap.put(nums[i],i); } return null; } }