华为OD后端开发岗笔面试记录

import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Exm1 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str1 = in.nextLine();
        String str2 = in.nextLine();

        //先算str2
        int str2Count = countChars(str2);

        //分割str1
        String[] strInStr1 = str1.split("[0-9a-f]"); // 有空字符串
        Arrays.sort(strInStr1, new Comparator<String>() {
            @Override
            public int compare(String o1, String o2) {
                return countChars(o1) != countChars(o2) ? countChars(o2) - countChars(o1) : o2.compareTo(o1);
            }
        });

        for (String s : strInStr1) {
            int curCount = countChars(s);
            if (curCount <= str2Count && curCount != 0) {
                System.out.println(s);
                return;
            }
        }
    }

    private static int countChars(String str) {
        int[] strCount = new int[26];
        for(char c : str.toCharArray()) {
            int idx = c - 'a';
            strCount[idx] = 1;
        }
        int charCount = 0;
        for(int i = 0; i < 26; i++) charCount += strCount[i];
        return charCount;
    }
}

import java.util.Arrays;
import java.util.Scanner;

public class Exm2 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String[] input = in.nextLine().split(",");
        int time1 = Integer.parseInt(input[0]);
        int time2 = Integer.parseInt(input[1]);
        int totalNum = Integer.parseInt(input[2]);

        int[] res = new int[totalNum+1];
        int minTime = Math.min(time1, time2);
        int maxTime = Math.max(time1, time2);
        int curTime = minTime * totalNum;
        res[0] = curTime;
        System.out.printf("[%d, ", res[0]);
        for(int i = 1; i < totalNum+1; i++) {
            curTime = curTime - minTime + maxTime;
            res[i] = curTime;
            if(i != res.length-1) System.out.printf("%d, ", res[i]);
            else System.out.print(res[i]);
        }
//
//        //打印[3, 4, 5, 6]
//        System.out.print("[");
//        for(int i = 0; i < res.length; i++) {
//            if(i != res.length-1) System.out.printf("%d, ", res[i]);
//            else System.out.print(res[i]);
//        }
        System.out.println("]");
        // System.out.println(Arrays.toString(res));
    }
}

import java.util.*;

public class Exm3 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 构建树
        //创建节点
        int num = Integer.parseInt(in.nextLine());
        TreeNode[] nodes = new TreeNode[num];
        List<Integer>[] childs = new List[num];
        for(int i = 0; i < num; i++) {
            String[] line = in.nextLine().split("\\s+");
            nodes[i] = new TreeNode(Integer.parseInt(line[0]));
            childs[i] = new ArrayList<Integer>();
            for(int j = 1; j < line.length; j++) childs[i].add(Integer.valueOf(line[j]));
        }

        //连接节点
        for(int i = 0; i < num; i++) {
            List<Integer> cs = childs[i];
            TreeNode curNode = nodes[i];
            for(int idx : cs) {
                curNode.childs.add(nodes[idx]);
            }
        }
        TreeNode root = nodes[0];

        // 构建完成
        // 用队列进行层次遍历
        String[] loc = in.nextLine().split("\\s+");
        int x = Integer.parseInt(loc[0]);
        int y = Integer.parseInt(loc[1]);
        Queue<TreeNode> queue = new ArrayDeque<TreeNode>();
        int curRow = 0;
        queue.offer(root);
        int curLineNum = 1;
        int nextLineNum = 0;
        while(curRow < x && !queue.isEmpty()) {
            TreeNode cur = queue.poll();
            List<TreeNode> curChilds = cur.childs;
            for(TreeNode child : curChilds) {
                queue.offer(child);
                nextLineNum++;
            }
            curLineNum--;
            if(curLineNum == 0) {
                curLineNum = nextLineNum;
                nextLineNum = 0;
                curRow++;
            }
        }

        if(queue.isEmpty()) {
            System.out.println("{}");
            return;
        }
        //寻找y
        for(int j = 0; j < y && !queue.isEmpty(); j++) {
            queue.poll();
        }

        if(queue.isEmpty()) {
            System.out.println("{}");
            return;
        } else System.out.printf("{%d}\n", queue.poll().value);
    }

    private static class TreeNode {
        int value;
        List<TreeNode> childs = new ArrayList<>();
        private TreeNode(int value, List<TreeNode> childs) {
            this.value = value;
            this.childs = childs;
        }

        private TreeNode(int value) {
            this.value = value;
        }
    }
}