leetcode 1 两数之和

Posted 2022-10-08 fazero

https://leetcode-cn.com/problems/two-sum/

暴力，复杂度n的平方

var twoSum = function(nums, target) 
    let arr = []
    for (let i = 0; i < nums.length;i++) 
        for (let j = i + 1; j < nums.length;j++) 
            if (nums[i] + nums[j] === target) 
                arr.push(i)
                arr.push(j)
            
        
    
    return arr;
;

复杂度2n

var twoSum = function (nums, target) 
    let map = new Map();
    let arr = new Array();
    for (let i = 0; i < nums.length; i++) 
        map.set(nums[i], i)
    
    for (let i = 0; i < nums.length; i++) 
        if (map.has(target - nums[i]) && map.get(target - nums[i]) !== i) 
            arr.push(i,map.get(target - nums[i]));
            return arr;