Code : Olympic Tin Hoc Bach Khoa - vessel Program ( 2011 - 2012)

//bai chi  la y chinh de tinh ra so lo duoc bao ve an toan. chay tren cac ban cua tuboC,bonland C .neu chay tren tool bdanh cho lap trinh huong doi tuong thi doi void thanh int main.

#include <conio.h>
#include <stdio.h>
void main()
{
   int m[100][100];
   int i,x,y,k[100],l[100],n;
   int temp=0,dem=0;
   int rong,dai;
   do{
         printf("\n nhap vao do dai va rong bai bien cua ban");
         printf("\n rong=");scanf("%d",&rong);
         printf("\n dai=");scanf("%d",&dai);
         for(x=0;x<rong;x++)
         for(y=0;y<dai;y++)
                  m[x][y]=0;//khoi tao vung bien chua duoc bao ve.
      printf("\n ban muon chon may lo de bao ve:");
      scanf("%d",&n);
         if(n==0) temp=1;
           else {
                  printf("\n nhap vao dia chi cac lo:");
                   for(i=1;i<=n;i++)
                          {
                           printf("k[%d]=",i);
                          scanf("%d",&k[i]);
                           printf("l[%d]=",i);
                           scanf("%d",&l[i]);
                          }
                  for(x=0;x<rong;x++)
                      for(y=0;y<dai;y++)
                        {
                         for(i=1;i<=n;i++)
                         if(x==k[i] && y==l[i])
                                {
                                m[x-1][y-1]=1;  m[x][y-1]=1;   m[x+1][y-1]=1;
                                m[x-1][y]=1;    m[x][y]=1;     m[x+1][y]=1;
                                m[x-1][y+1]=1;   m[x][y+1]=1;   m[x+1][y+1]=1;
                                }
                        }
           }
   for(x=0;x<rong;x++)
              for(y=0;y<dai;y++)
                     if(m[x][y]==1) dem++;
  printf("\n so lo duoc bao ve an toan la:%d",dem);
  dem=0;
          }while(!temp);
}