Day07-06_13【CT】LeetCode手撕—1. 两数之和

题目

• 原题连接：1. 两数之和

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1-思路

哈希表

• 利用哈希表存储 key 数组元素值 ——> value 数组下标
• 遍历数组

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2- 实现

⭐1. 两数之和——题解思路

class Solution {public int[] twoSum(int[] nums, int target) {int[] res = new int[2];// 哈希表Map<Integer,Integer> map = new HashMap<>();// 存 key 值 ——> value 下标// 遍历数组for(int i  = 0 ; i < nums.length ;i++){if(map.containsKey(target-nums[i])){res[0] = i;res[1] = map.get(target-nums[i]);}map.put(nums[i],i);}return res;}
}

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3- ACM实现

public class twoSum {public static int[] twoSum(int[] nums, int target) {int[] res = new int[2];// 哈希表Map<Integer,Integer> map = new HashMap<>();// 存 key 值 ——> value 下标// 遍历数组for(int i  = 0 ; i < nums.length ;i++){if(map.containsKey(target-nums[i])){res[0] = i;res[1] = map.get(target-nums[i]);}map.put(nums[i],i);}return res;}public static void main(String[] args) {Scanner sc = new Scanner(System.in);System.out.println("输入数组长度");int n = sc.nextInt();int[] nums = new int[n];for(int i = 0 ; i < n;i++){nums[i] = sc.nextInt();}System.out.println("输入目标和");int target = sc.nextInt();int[] forRes = twoSum(nums,target);for(int i : forRes){System.out.print(i+" ");}}
}