poj2704

简单dp

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
using namespace std;

#define maxn 50

char map[maxn][maxn];
long long f[maxn][maxn];
int n;

void input()
{
    for (int i = 0; i < n; i++)
        scanf("%s", map[i]);
}

void work()
{
    memset(f, 0, sizeof(f));
    f[0][0] = 1;
    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
        {
            for (int k = 0; k < i; k++)
                if (map[k][j] - '0' + k == i)
                    f[i][j] += f[k][j];
            for (int k = 0; k < j; k++)
                if (map[i][k] - '0' + k == j)
                    f[i][j] += f[i][k];
        }
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d", &n), n != -1)
    {
        input();
        work();
        printf("%lld\n", f[n - 1][n - 1]);
    }
    return 0;
}