leetcode 打卡，1. 两数之和

我乃小神神

发布于 2022-05-11 00:47:50

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代码可运行

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代码可运行

单纯记录一下自己要刷题的日子 2022年5月10号目前凌晨12:14

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		输入：nums = [2,7,1,15], target = 9
		输出：[0,1]

	</body>
	<script>
		let nums = [2, 7, 0, 3, 4]
		let target = 9
		// 1:使用map 解
		var oneSum = function(nums, target) {
			const map = new Map()
			for (let i = 0; i < nums.length; i++) {
				const otherIndex = map.get(target - nums[i])
				if (otherIndex !== undefined) {
					//能匹配到返回当前map 中的value，及其当前的下标
					return [otherIndex, i]
				}
				//先存起来
				map.set(nums[i], i)
			}
		};
		console.log("1:使用map 解", oneSum(nums, target))
		// 2:直接for 循环匹配差值
		var twoSum = function(nums, target) {
			for (let i = 0; i < nums.length; i++) {
				let num = target - nums[i]
				let res1 = i
				let res2 = nums.indexOf(num, i + 1);
				if (res2 !== -1) {
					return [res1, res2]
				}
			}
		};
		console.log("2.直接for 循环匹配差值", twoSum(nums, target))
		// 3:直接for 循环
		var threeSum = function(nums, target) {
			for (let i = 0, len = nums.length; i < len - 1; i++) {
				for (let j = i + 1; j < len; j++) {
					if (nums[i] + nums[j] == target) {
						return [i, j]
					}
				}
			}
		};
		console.log("3:直接for 循环", threeSum(nums, target))
		// 4:map 哈希
		var fourSum = function(nums, target) {
		    const map = new Map()
		    for(let i = 0; i < nums.length; i++) {
		        const d = target - nums[i]
		        if(map.has(d)) {
		            return [map.get(d), i]
		        }
		        map.set(nums[i], i)
		    }
		};
		console.log("4:map 哈希", fourSum(nums, target))
		
	</script>
</html>