B1027 print hourglass

1027 Print hourglass (20 branch )

This question requires you to write a program to print the given symbol into the shape of an hourglass . For example, given 17 individual “*”, It is required to print in the following format

*****
 ***
  *
 ***
*****

So-called “ Hourglass shape ”, Refers to the output of odd symbols per line ; Align symbol centers ; Number difference between two adjacent lines of symbols 2; The number of symbols decreases from large to small to 1, Increase from small to large ; Equal number of first and last symbols .

Given arbitrary N Symbols , It doesn't have to be an hourglass . Require the printed hourglass to use as many symbols as possible .

Input format ：
Type in on a line to give 1 A positive integer N（≤1000） And a symbol , Space between

Output format ：
First print out the largest hourglass shape made up of the given symbols , Finally, output the number of unused symbols in one line .

sample input

19 *

sample output

*****
 ***
  *
 ***
*****
2

Topic analysis ：

1. Find the mathematical law, namely the number of inverted triangle lines k Satisfy 2kk-1 Equal to the number of points in the graph
2. adopt k Value binding cycle for printing

The code is as follows ：

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    char a;
    cin>>n>>a;
    int k=1;
    while(k*k*2-1<=n){
    	k++;
	}
	k--;
    for(int i=k;i>0;i--){
		for(int m=0;m<k-i;m++){
			cout<<" ";
		}
		for(int j=0;j<2*i-1;j++){
			cout<<a;
		}
		cout<<endl;
	}
	for(int i=1;i<k;i++){
		for(int m=0;m<k-i-1;m++){
			cout<<" ";
		}
		for(int j=0;j<2*i+1;j++){
			cout<<a;
		}
		cout<<endl;
	}
    
    int x=n-k*k*2+1;
    (x)?printf("%d",x):printf("0");
    
    return 0;
}