1. 两数之和 - 力扣（LeetCode）

一、Java

import java.util.HashMap;class Solution {public int[] twoSum(int[] nums, int target) { //返回数组HashMap<Integer, Integer> map = new HashMap<>(); //键：元素值；值：元素索引for (int i = 0; i < nums.length; i++) {if (map.containsKey(target - nums[i]))return new int[]{map.get(target - nums[i]), i};elsemap.put(nums[i], i);}return null;}
}

二、C++

#include <vector>
#include <unordered_map>
using namespace std;
class Solution {
public:vector<int> twoSum(vector<int>& nums, int target) {unordered_map<int, int> m; //unordered_map：哈希映射for (int i = 0; i < nums.size(); i++) {if (m.find(target - nums[i]) != 0)return {m[target - nums[i]], i};elsem.insert({nums[i], i});}return {};}
};

三、Python

from typing import Listclass Solution:def twoSum(self, nums: List[int], target: int) -> List[int]:m = {}for i in range(len(nums)):if target - nums[i] in m:return [m[target - nums[i]], i]else:m[nums[i]] = i

四、JavaScript

var twoSum = function(nums, target) {let m = new Map();for (let i = 0; i < nums.length; i++) {if ( m.has(target - nums[i]))return [m.get(target - nums[i]), i];elsem.set(nums[i], i); }
};

五、Go

package mainfunc twoSum(nums []int, target int) []int {m := make(map[int]int)for i := 0; i < len(nums); i++ {if idx, ok := m[target-nums[i]]; ok {return []int{idx, i}} else {m[nums[i]] = i}}return []int{}
}