[UVa] 352 The Seasonal War.cpp

#include <cstdio>
using namespace std;

char image[30][30];

void DFS(int &n, int i, int j)
{
    image[i][j] = '0';
    if (i-1 >= 0 && image[i-1][j] == '1') DFS(n, i-1, j);
    if (i+1 <  n && image[i+1][j] == '1') DFS(n, i+1, j);
    if (j-1 >= 0 && image[i][j-1] == '1') DFS(n, i, j-1);
    if (j+1 <  n && image[i][j+1] == '1') DFS(n, i, j+1);
    if (i-1 >= 0 && j-1 >= 0 && image[i-1][j-1] == '1') DFS(n, i-1, j-1);
    if (i-1 >= 0 && j+1 <  n && image[i-1][j+1] == '1') DFS(n, i-1, j+1);
    if (i+1 <  n && j-1 >= 0 && image[i+1][j-1] == '1') DFS(n, i+1, j-1);
    if (i+1 <  n && j+1 <  n && image[i+1][j+1] == '1') DFS(n, i+1, j+1);
}

int main()
{
   // freopen ("input.txt","rt",stdin);
    int n,Case = 1;
    while (scanf("%d", &n) != EOF){
        getchar();
        for (int i = 0; i < n; ++i)
            gets(image[i]);
        int num = 0;
        for (int i = 0; i < n; ++i)
            for (int j = 0; j < n; ++j)
                if (image[i][j] == '1'){
                    DFS(n, i, j);
                    ++num;
                }
        printf("Image number %d contains %d war eagles.\n", Case++, num);
    }
    return 0;
}