Java print hourglass PTA

Learning job record

This question asks you to write a program to print a given symbol into an hourglass shape. 17 example given, "*", the following format printing requires

The so-called "hourglass shape" refers to each row outputs odd symbols; symbol center of each row are aligned; the difference between the number of symbols two adjacent rows 2; the number of symbols in descending order of descending to the first one, then the order of small to large increments; inclusive symbol equal numbers.

Given any N symbols, not necessarily exactly composed of an hourglass. Requirements can be printed out as much of the hourglass symbol.

Input formats:

Input gives a positive integer N (≤1000) and a symbol in a row, separated by a space.

Output formats:

First print largest hourglass shape consisting of a given symbol, the symbol number output last remaining useless fall in a row.

Sample input:

19 *

Sample output:

Code

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in) ;
        int N = scanner.nextInt() ;
        String  c =scanner.next();
        int num ,sum ,s;
        for(num = 1 ; ; num++){
            if(2 * num*(num + 2) + 1 > N){
                num--;
                break;
            }
        }
        s=2*num+1;

        for(int r=0;r<s;r++) {
            if (r <= num) {
                for (int a = 0; a < s-r; a++) {
                    if (a < r) {
                        System.out.print(' ');
                    } else {
                        System.out.print(c);
                    }
                }
            } else {
                for (int a = 0; a < r+1; a++) {
                    if (a < s-r-1) {
                        System.out.print(' ');
                    } else {
                        System.out.print(c);
                    }
                }
            }
            System.out.println();
        }
        sum=2 * num*(num + 2) + 1;
        if(N>=sum){
            System.out.print(N-sum);
        }

    }
}