1. 修建灌木

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int n = scan.nextInt();for (int i = 1;i < n+1;i++){int distance = Math.max(i-1,n-i);System.out.println(distance*2);}scan.close();}
}

 2. 最少砝码

import java.util.Scanner;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);long target = scan.nextLong();int num = 1;long weight = 1l;long total = 1l;while (total < target){num ++;weight *= 3;total += weight;}System.out.print(num);scan.close();//只有一个砝码 1//只有两个砝码 4: 1 3//只有三个砝码 13}
}

3. 求和

import java.util.Scanner;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int num = scan.nextInt();long arr[] = new long[num];long sum = 0l;for(int i = 0;i<arr.length;i++){arr[i] = scan.nextLong();sum += arr[i];}long total = 0l;for (int j = 0;j<arr.length;j++){total += arr[j] * (sum - arr[j]);sum -= arr[j];}System.out.println(total);scan.close();}
}

4. 成绩分析

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int num = scan.nextInt();int arr[] = new int[num];double sum = 0;for(int i = 0;i < arr.length;i++){arr[i] = scan.nextInt();sum += arr[i];}double average = sum / num;int min = arr[0];int max = arr[0];for(int j =0;j<arr.length;j++){if(arr[j] > max){max = arr[j];}if(arr[j] < min){min = arr[j];}}System.out.println(max);System.out.println(min);System.out.printf("%.2f",average);scan.close();}
}//用sort
import java.util.Scanner;
import java.util.Arrays;public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int num = scan.nextInt();int arr[] = new int[num];double sum = 0;for(int i = 0;i < arr.length;i++){arr[i] = scan.nextInt();sum += arr[i];}double average = sum / num;Arrays.sort(arr);System.out.println(arr[num-1]);System.out.println(arr[0]);System.out.printf("%.2f",average);scan.close();}
}

5. 合法日期

import java.util.Scanner;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int month = scan.nextInt();int day = scan.nextInt();int[] a = {31,28,31,30,31,30,31,31,30,31,30,31};if(month <= 12 && day <= a[month-1]){System.out.println("yes");}else{System.out.println("no");}scan.close();}
}

6. 时间加法

import java.util.Scanner;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int a = scan.nextInt();int b = scan.nextInt();int t = scan. nextInt();a += (b+t)/60;b = (b+t)%60;System.out.println(a);System.out.println(b);scan.close();}
}

7. 扫雷

import java.util.*;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int hang = scan.nextInt();int lie = scan.nextInt();int a[][] = new int[hang+2][lie+2];for(int i = 1;i<hang+1;i++){for (int j =1;j<lie+1;j++){a[i][j] = scan.nextInt();}}for(int i = 1;i<hang+1;i++){for(int j =1;j<lie+1;j++){if(a[i][j] == 1){System.out.print(9 + " ");}else{System.out.print(a[i-1][j-1]+a[i-1][j]+a[i-1][j+1]+a[i][j-1]+a[i][j+1]+a[i+1][j-1]+a[i+1][j]+a[i+1][j+1] + " ");}}System.out.println();}scan.close();}
}

8. 大写

import java.util.*;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);String zifuchuan = scan.next();System.out.print(zifuchuan.toUpperCase());scan.close();}
}

9. 标题统计

import java.util.Scanner;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);String title = scan.nextLine().replace(" ","");System.out.print(title.length());scan.close();}
}

nextLine()可以接受空格 

10. 求和

 

import java.util.*;
public class Main {public static void main(String[] args) {int sum = 0;for (int i=1;i<=2019;i++){String shuzi = String.valueOf(i);if (shuzi.contains("2") || shuzi.contains("0") || shuzi.contains("1") || shuzi.contains("9")){sum += i;}}System.out.print(sum);}
}

11. 天数

import java.util.*;
public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int month = scan.nextInt();int[] a = {31,28,31,30,31,30,31,31,30,31,30,31};System.out.print(a[month-1]);scan.close();}
}

 12. 最大间隙

import java.util.*;public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int len = scan.nextInt();int arr[] = new int[len];for (int i =0;i<arr.length;i++){arr[i] = scan.nextInt();}int max = 0;int low = 0;int fast = 1;int cha = 0;while(fast <= arr.length-1){cha = arr[fast] - arr[low];if(cha > max){max = cha;}low++;fast++;}System.out.print(max);scan.close();}
}

13. 金币

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner scan = new Scanner(System.in);int day = scan.nextInt();int i = 0;int count = 1;int money =0;while(i<day){money += count*count;i += count++;}if(i>day){money -= (i-day)*(count-1);}System.out.print(money);scan.close();}
}