小测验-基础算法1

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#include <stdio.h> 
#include <string.h> 
#define SIZE 100 
int n, m, p, count; 
int a[SIZE][SIZE]; 
void colour(int x, int y) 
{ 
 count++; 
 a[x][y] = 1; 
 if ((x > 1) && (a[x - 1][y] == 0)) 
  colour(x - 1, y); 
 if ((y > 1) && (a[x][y - 1] == 0)) 
  colour(x, y - 1); 
 if ((x < n) && (a[x + 1][y] == 0)) 
  colour(x + 1, y); 
 if ((y < m) && (a[x][y + 1] == 0)) 
  colour(x, y + 1);  
} 
int main() 
{ 
 int i, j, x, y, ans; 
 memset(a, 0, sizeof(a)); 
 scanf("%d%d%d", &n, &m, &p); 
 for (i = 1; i <= p; i++) { 
  scanf("%d%d", &x, &y); 
  a[x][y] = 1; 
 } 
 ans = 0;
for (i = 1; i <= n; i++) 
  for (j = 1; j <= m; j++) 
   if (a[i][j] == 0) { 
    count = 0; 
    colour(i, j); 
    if (ans < count) 
     ans = count; 
   } 
 printf("%d\n", ans); 
 return 0; 
}