ACM模式——11-15

雨年

rainyak

11. 共同祖先

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        
        while(in.hasNext()){
            int n = in.nextInt();
            int[] arr = new int[31];
            
            for(int i = 0;i < n; i++){
                int a = in.nextInt();
                int b = in.nextInt();
                
                arr[a] = b;
            }
            
            int count_a = 0;
            int count_b = 0;
            int now_a = 1;
            int now_b = 2;
            
            while(arr[now_a] != 0){
                count_a++;
                now_a = arr[now_a];
            }
            
            while(arr[now_b] != 0){
                count_b++;
                now_b = arr[now_b];
            }
            
            if(count_a > count_b){
                System.out.println("You are my elder");
                
            }else if(count_a < count_b){
                System.out.println("You are my younger");
            }else{
                System.out.println("You are my brother");
            }
        }
    }
}

12. 打印数字图形

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        Solution solution  = new Solution();
        while(in.hasNext()){
            int num = in.nextInt();
            solution.drawNum(num);
        }
        
    }
}

class Solution{
    public void drawNum(int num){
        int space = num  - 1;
        int count = 0;
        //上半三角
        for(int i = 1;i <= num; i++){
            count++;
            space--;
            //空格打印
            for(int j = space;j >= 0; j--){
                System.out.printf(" ");
            }
            //递增打印
            for(int k = 1;k <= count; k++){
                System.out.printf("%d", k);
            }
            //递减打印
            for(int k = count - 1;k >= 1; k--){
                System.out.printf("%d", k);
            }
            
            System.out.println("");
        }
        //下半三角
        for(int i = num - 1;i >= 1; i--){
            count--;
            space++;
            //空格打印
            for(int j = space;j >= 0; j--){
                System.out.printf(" ");
            }
            //递增打印
            for(int k = 1;k <= count; k++){
                System.out.printf("%d", k);
            }
            //递减打印
            for(int k = count - 1;k >= 1; k--){
                System.out.printf("%d", k);
            }
            
            System.out.println("");
        }
    }
}

13. 镂空三角形

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        Solution solution = new Solution();
        
        while(in.hasNext()){
            char c = in.next().charAt(0);
            if (!in.hasNextInt()) {
                break;
            }
            int len = in.nextInt();
            solution.drawS(c, len);
            System.out.println("");
        }
    }
}

class Solution{
    public void drawS(char c, int len){
        int space = len  - 1;
        int p = 1;
        //三角
        for(int i = 1;i <= len; i++){
            space--;
            
            //空格打印
            for(int j = space;j >= 0; j--){
                System.out.printf(" ");
            }
            //递增打印
            for(int k = 1;k <= p; k++){
                if(i != len){
                    if(k == 1){
                        System.out.printf("%c", c);
                    }else if(k == p){
                        System.out.printf("%c", c);
                    }else{
                        System.out.printf(" ");
                    }
                }else{
                    System.out.printf("%c", c);
                }
            }
            
            p+= 2;
            
            System.out.println("");
        }
    }
}

14. 句子缩写

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        
        int n = in.nextInt();
        in.nextLine(); // 读取并丢弃换行符
        
        for(int i = 0;i < n; i++){
            //想要将输入的字符串按照空格进行分割，并且不包含空格子字符串。
            //可以使用split("\s+")方法。
            StringBuffer result = new StringBuffer();
            String[] str = in.nextLine().split("\\s+");
            
            int len = str.length;
            
            for(int j = 0;j < len; j++){
                if(str[j].charAt(0) > 'A'){
                    result.append(Character.toUpperCase(str[j].charAt(0)));
                }else{
                    result.append(str[j].charAt(0));
                }
            }
            
            System.out.println(result.toString());
        }
    }
}

15. 神秘字符

import java.util.*;

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        
        int n = in.nextInt();
        in.nextLine();
        
        for(int i = 0;i < n; i++){
            StringBuilder str1 = new StringBuilder(in.nextLine());
            StringBuilder str2 = new StringBuilder(in.nextLine());
            
            int len = str1.length();
            str1.insert(len / 2, str2);
            
            System.out.println(str1);
        }
    }
}

没想到时隔那么久还有要写画图的代码哈哈，比大一时顺畅多了，基本随便写就行。

15题注意StringBuilder insert的用法。这时候在复习一下：

String、StringBuffer、StringBuilder的区别？

String：底层构建使用final关键字，故不可编辑。

StringBuffer：可以编辑，线程安全型，在并发时使用。

StringBuilder：可以编辑，线程不安全型，相比StringBuffer损耗小，常用。