http://hihocoder.com/problemset/problem/1454

调了好长时间，谜之WA。。。

等我以后学好dp再来看为什么吧，先弃坑(╯‵□′)╯︵┻━┻

#include<cstdio>

#include<cstring>

#include<algorithm>

using namespace std;

typedef long long ll;

const int pp = 998244353;

const int N = 503;

int f[N][N], g[N][N], n;

char A[N], B[N];

int main() {

//	freopen("B.in", "r", stdin);

	scanf("%d", &n);

	scanf("%s%s", A + 1, B + 1);

	for (int i = 1; i <= n; ++i) {

		if (A[i] == '1') continue;

		g[i][i] = f[i][i] = 1;

	}

	if (B[1] == '1') {puts("0"); return 0;}

	for (int p = 2; p <= n; ++p)

		for (int j = p, i = 1; j <= n; ++j, ++i) {

			if (A[i] != '0') f[i][j] = g[i + 1][j];

			if (A[i] != '0') {

				if (B[i] == '0') g[i][j] = f[i][j];

				else {

					if (B[i] == '?') g[i][j] = f[i][j];

					for (int k = i; k < j; ++k)

						g[i][j] = (g[i][j] + ((int) (1ll * f[i][k] * g[k + 1][j] % pp))) % pp;

				}

			} else {

				if (B[i] != '0') g[i][j] = g[i + 1][j];

			}

		}

	printf("%d\n", f[1][n]);

	return 0;

}