传送门
题解
#include <cstdio>
#include <iostream>
#define N 802
#define mod 1000000007
int n, m, p, ans;
int a[N][N], f[N][N][16][2];
inline int read()
{
int x = 0, f = 1;
char ch = getchar();
for(; !isdigit(ch); ch = getchar()) if(ch == '-') f = -1;
for(; isdigit(ch); ch = getchar()) x = (x << 1) + (x << 3) + ch - '0';
return x * f;
}
int main()
{
int i, j, k;
n = read();
m = read();
p = read() + 1;
for(i = 1; i <= n; i++)
for(j = 1; j <= m; j++)
f[i][j][(a[i][j] = read()) % p][0] = 1;
for(i = 1; i <= n; i++)
for(j = 1; j <= m; j++)
{
for(k = 0; k < p; k++)
{
f[i + 1][j][(k + a[i + 1][j]) % p][0] = (f[i + 1][j][(k + a[i + 1][j]) % p][0] + f[i][j][k][1]) % mod;
f[i + 1][j][(k - a[i + 1][j] + p) % p][1] = (f[i + 1][j][(k - a[i + 1][j] + p) % p][1] + f[i][j][k][0]) % mod;
f[i][j + 1][(k + a[i][j + 1]) % p][0] = (f[i][j + 1][(k + a[i][j + 1]) % p][0] + f[i][j][k][1]) % mod;
f[i][j + 1][(k - a[i][j + 1] + p) % p][1] = (f[i][j + 1][(k - a[i][j + 1] + p) % p][1] + f[i][j][k][0]) % mod;
}
ans = (ans + f[i][j][0][1]) % mod;
}
printf("%d\n", ans);
return 0;
}