1.题目要求

2.代码详情

java:暴力求解法+hashmap法

class Solution {// 方法一：暴力求解法// public int[] twoSum(int[] nums, int target) {//     int n = nums.length;//     for (int i=0; i<n; i++){//         for (int j=i+1; j<n; j++){//             if (nums[i]+nums[j] == target){//                 return new int[]{i,j};//             }//         }//     }//     return null;// }// 方法二：hashmap方法public int[] twoSum(int[] nums, int target) {Map<Integer,Integer> hashmap = new HashMap<Integer,Integer>();for(int i=0; i<nums.length; i++){if (hashmap.containsKey(target-nums[i])){int j=hashmap.get(target-nums[i]);return new int[]{j,i};}hashmap.put(nums[i],i);}return new int[0];}
}

python:暴力求解：

class Solution:def twoSum(self, nums: List[int], target: int) -> List[int]:for i in range(len(nums)):for j in range(i+1,len(nums)):if nums[i]+nums[j]==target:return [i,j]return []

python:排序+双指针

class Solution:def twoSum(self, nums: List[int], target: int) -> List[int]:temp = nums.copy()temp.sort()i=0j = len(nums)-1while i < j:if (temp[i] + temp[j]) > target:j -= 1elif (temp[i] + temp [j]) < target:i += 1else:break              p = nums.index(temp[i])nums.pop(p)k = nums.index(temp[j])if k >= p:k = k+1return [p, k]