codevs 1160 蛇形矩阵

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<string>
#include<algorithm>
#include<iomanip>
using namespace std;
int a[101][101]={0};
int main()
{
    int n,tot=1;
    cin>>n;
    int i=(n+1)/2;
    int j=(n+1)/2;
    a[i][j]=tot;
    int m=i;
    int p=j;
    for(int w=1;w<=(n-1)/2;w++)
    {
    while(p<j+w)
     {
         tot++;
        p++;
         a[m][p]=tot;
        }    
    while(m>(i-w))
     {
         m--;
         tot++;
         a[m][p]=tot;
          }     
     while(p>j-w)
      {
          p--;
          tot++;
          a[m][p]=tot;
            }
    while(m<i+w)
     {
         m++;
         tot++;
         a[m][p]=tot;
           }
           while(p<j+w)
     {
         tot++;
        p++;
         a[m][p]=tot;
        }
    }    
    int sum=0;          
     for(int i=1;i<=n;i++)
      {
          for( j=1;j<=n;j++)
           {
               if(i==j||i+j==n+1)
                {
                    sum+=a[i][j];
                }
           }  
              }
     for(int i=1;i<=n;i++)
      {
          for( j=1;j<=n;j++)
           {
            cout<<a[i][j]<<" ";
         }
            cout<<endl;    
     }       
     cout<<sum<<endl;
    return 0;          
}