AI平台星环科技23届-后端开发工程师

星环科技笔试编程题1
package com.xinghuan;// code1import java.util.HashMap;import java.util.Map;import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner in = new Scanner(System.in);int t = in.nextInt();for (int i = 0; i < t; i++) {int n = in.nextInt();int[] nums = new int[n];for (int j = 0; j < n; j++) {nums[j] = in.nextInt();nums[j] -= j;}Solutions sol = new Solutions();System.out.println(sol.calcCnt(nums));}}}class Solutions {public int calcCnt(int[] nums) {int len = nums.length;int cnt = 0;HashMap hashMap = new HashMap<>();for (int i = 0; i < len; i++) {hashMap.put(nums[i], hashMap.getOrDefault(nums[i], 0) + 1);}for (Map.Entry entry : hashMap.entrySet()) {int temp = entry.getValue();if (temp <= 1)continue;cnt += temp * (temp-1) / 2;}return cnt;}}
通过90%测试案例，不知道什么地方出现了问题
编程题2

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package com.xinghuan;import java.util.HashMap;import java.util.Map;import java.util.Scanner;public class Main {static int[][] directions = new int[][]{{0, 1}, {0, -1}, {1, 0}, {-1, 0}};static HashMap hashMap = new HashMap<>();public static void main(String[] args) {Scanner in = new Scanner(System.in);int n = in.nextInt();int[][] nums= new int[n][n];for (int i = 0; i < n; i++) {for (int j = 0; j < n; j++) {nums[i][j] = in.nextInt();}}dfs(nums, n-1, n-1, 0);int max_steps = Integer.MAX_VALUE;int choices = 0;for (Map.Entry entry : hashMap.entrySet()) {int step = entry.getKey();int choice = entry.getValue();if (max_steps > step) {max_steps = step;choices = choice;}}System.out.println(max_steps);System.out.println(choices);}public static void dfs(int[][] nums, int i, int j, int cnt) {// reach termialint n = nums.length;if (i == 0 && j == 0) {hashMap.put(cnt, hashMap.getOrDefault(cnt, 0) + 1);return ;}// not reachableif (i >= n || i < 0 || j >= n || j < 0 || nums[i][j] == 0)return ;// other wayfor (int d = 0; d < 4; d++) {nums[i][j] = 0;dfs(nums, i + directions[d][0], j + directions[d][1], cnt+1);nums[i][j] = 1;}}}

没有完全AC…
编程题3

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做到这道题已经过了一个小时，而且这个题看着实在是有点麻烦，大概是改进版本的后缀表达式计算，写起来有点麻烦，没有写了。。。
总结
【AI平台星环科技23届-后端开发工程师】数据结构忘得差不多了，最近一直在弄项目和背八股文，疏忽了刷题，回溯和后缀表达式以及字符串读入需要好好加强一下

AI平台 星环科技23届-后端开发工程师

AI平台星环科技23届-后端开发工程师