4094. Spiral matrix

Given you a n*m matrix, you task is to output the corresponding Spiral matrix whose row is n and column is m.
For example:
1 2 3 4 5
16 17 18 19 6
15 24 25 20 7
14 23 22 21 8
13 12 11 10 9

Input

The input consists of two integers n and m. (1≤n,m≤200))

Output

Output the corresponding Spiral matrix.

Sample Input

5 5

Sample Output

1 2 3 4 5
16 17 18 19 6
15 24 25 20 7
14 23 22 21 8

13 12 11 10 9

#include<stdio.h>
#include<string>
#include<cstring>
int main()
{
	int n,m,flag=0,a[40001],b[200][200];
	while(scanf("%d%d",&n,&m)!=EOF){
	int i=0,j=0;
	for(i=1;i<=m*n;i++)
		a[i]=i;
	i=0;
	j=0;
	flag=0;
	int x=n;
	int y=m;
	memset(b,0,sizeof(b));
	for(int k=1;k<=m*n;k++)
	{
		if(flag==0)
		{
			b[i][j]=a[k];
			//printf("%d\n",b[i][j]);
			if(j==m-1||b[i][j+1])
			{
			  flag=1;
			  i++;
			  continue;
			}	
		//	b[i][j]=a[k];
			j++;
		}
		//printf("j=%d\n",j);
		else if(flag==1)
		{	
			b[i][j]=a[k];
			if(i==n-1||b[i+1][j])
			{
				flag=2;
				j--;
				continue;
			}
			//b[i][j]=a[k];
			i++;
		}
		else if(flag==2)
		{
			b[i][j]=a[k];
			if(k==2*m+n-2||b[i][j-1])
			{
				flag=3;
				i--;
				continue;
			}
			//b[i][j]=a[k];
			j--;
		}
		else if(flag==3)
		{
			//i--;
			b[i][j]=a[k];
			if(b[i-1][j])
			{
				flag=0;
				j++;
				continue;
			}
			//b[i][j]=a[k];
			i--;
		}
	}
		for(i=0;i<n;i++){
			for(j=0;j<m;j++){
				printf("%d",b[i][j]);
				if(j!=m-1)
					printf(" ");
			}
		printf("\n");
		}
	}
	//system("pause");
	return 0;
}