# 地宫取宝 X 国王有一个地宫宝库,是 n×m 个格子的矩阵,每个格子放一件宝贝,每个宝贝贴着价值标签。 地宫的入口在左上角,出口在右下角。 小明被带到地宫的入口,国王要求他只能向右或向下行走。 走过某个格子时,如果那个格子中的宝贝价值比小明手中任意宝贝价值都大,小明就可以拿起它(当然,也可以不拿)。 当小明走到出口时,如果他手中的宝贝恰好是 k 件,则这些宝贝就可以送给小明。 请你帮小明算一算,在给定的局面下,他有多少种不同的行动方案能获得这 k 件宝贝。 **输入格式** 第一行 3 个整数,n,m,k,含义见题目描述。 接下来 n 行,每行有 m 个整数 Ci 用来描述宝库矩阵每个格子的宝贝价值。 **输出格式** 输出一个整数,表示正好取 k 个宝贝的行动方案数。 该数字可能很大,输出它对 1000000007 取模的结果。 **数据范围** ``` 1≤n,m≤50, 1≤k≤12, 0≤Ci≤12 ``` **输入样例1:** ``` 2 2 2 1 2 2 1 ``` **输出样例1:** ``` 2 ``` **输入样例2:** ``` 2 3 2 1 2 3 2 1 5 ``` **输出样例2:** ``` 14 ``` ## aop ### before ```cpp #include using namespace std; const int N = 55; const int MOD = 1e9 + 7; int dp[N][N][13][14]; int g[N][N]; int n, m, k; ``` ### after ```cpp ``` ## 答案 ```cpp int main() { cin >> n >> m >> k; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { cin >> g[i][j]; g[i][j]++; } } dp[1][1][1][g[1][1]] = 1; dp[1][1][0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { for (int u = 0; u <= k; u++) { for (int v = 0; v <= 13; v++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u][v]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u][v]) % MOD; if (u > 0 && v == g[i][j]) { for (int c = 0; c < v; c++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u - 1][c]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u - 1][c]) % MOD; } } } } } } int res = 0; for (int i = 0; i <= 13; i++) res = (res + dp[n][m][k][i]) % MOD; cout << res << endl; return 0; } ``` ## 选项 ### A ```cpp int main() { cin >> n >> m >> k; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { cin >> g[i][j]; g[i][j]++; } } dp[1][1][1][g[1][1]] = 1; dp[1][1][0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { for (int u = 0; u <= k; u++) { for (int v = 0; v <= 13; v++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u][v]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u][v]) % MOD; if (u > 0 && v == g[i][j]) { for (int c = 0; c < v; c++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j][u - 1][c]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u - 1][c]) % MOD; } } } } } } int res = 0; for (int i = 0; i <= 13; i++) res = (res + dp[n][m][k][i]) % MOD; cout << res << endl; return 0; } ``` ### B ```cpp int main() { cin >> n >> m >> k; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { cin >> g[i][j]; g[i][j]++; } } dp[1][1][1][g[1][1]] = 1; dp[1][1][0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { for (int u = 0; u <= k; u++) { for (int v = 0; v <= 13; v++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u][v]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u][v]) % MOD; if (u > 0 && v == g[i][j]) { for (int c = 0; c < v; c++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u - 1][c]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j][u - 1][c]) % MOD; } } } } } } int res = 0; for (int i = 0; i <= 13; i++) res = (res + dp[n][m][k][i]) % MOD; cout << res << endl; return 0; } ``` ### C ```cpp int main() { cin >> n >> m >> k; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { cin >> g[i][j]; g[i][j]++; } } dp[1][1][1][g[1][1]] = 1; dp[1][1][0][0] = 1; for (int i = 1; i <= n; i++) { for (int j = 1; j <= m; j++) { for (int u = 0; u <= k; u++) { for (int v = 0; v <= 13; v++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u][v]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u][v]) % MOD; if (u > 0 && v == g[i][j]) { for (int c = 0; c < v; c++) { dp[i][j][u][v] = (dp[i][j][u][v] + dp[i - 1][j][u][c]) % MOD; dp[i][j][u][v] = (dp[i][j][u][v] + dp[i][j - 1][u - 1][c]) % MOD; } } } } } } int res = 0; for (int i = 0; i <= 13; i++) res = (res + dp[n][m][k][i]) % MOD; cout << res << endl; return 0; } ```