代码

// Written By NewbieChd
#include <cstdio>
using namespace std;

const int mod = 1e9 + 7;
inline void swap(int& x, int& y) { x ^= y, y ^= x, x ^= y; }

int main() {
    int n, m, i, ans;
    scanf("%d%d", &n, &m);
    if (n > m)
        swap(n, m);
    
    if (n == 1) {
        ans = 2;
        for (i = 1; i < m; ++i)
            ans = (ans << 1) % mod;
    }
    
    if (n == 2) {
        ans = 12;
        for (i = 2; i < m; ++i)
            ans = 3ll * ans % mod;
    }
    
    if (n == 3) {
        ans = 112;
        for (i = 3; i < m; ++i)
            ans = 3ll * ans % mod;
    }
    
    if (n == 4) {
        if (m == 4)
            ans = 912;
        else {
            ans = 2688;
            for (i = 5; i < m; ++i)
                ans = 3ll * ans % mod;
        }
    }
    
    if (n == 5) {
        if (m == 5)
            ans = 7136;
        else {
            ans = 21312;
            for (i = 6; i < m; ++i)
                ans = 3ll * ans % mod;
        }
    }
    
    if (n == 6) {
        if (m == 6)
            ans = 56768;
        else {
            ans = 170112;
            for (i = 7; i < m; ++i)
                ans = 3ll * ans % mod;
        }
    }
    
    if (n == 7) {
        if (m == 7)
            ans = 453504;
        else {
            ans = 1360128;
            for (i = 8; i < m; ++i)
                ans = 3ll * ans % mod;
        }
    }
    
    if (n == 8) {
        if (m == 8)
            ans = 3626752;
        else {
            ans = 10879488;
            for (i = 9; i < m; ++i)
                ans = 3ll * ans % mod;
        }
    }
    
    printf("%d\n", ans);
    return 0;
}

评测结果