Description
Given a n × n matrix A and a positive integer k, find the sum S=A+A2+A3+…+Ak.
Input
The input contains exactly one test case. The first line of input contains three positive integers n (n ≤ 30), k (k ≤ 109) and m (m < 104). Then follow n lines each containing n nonnegative integers below 32,768, giving A’s elements in row-major order.
Output
Output the elements of S modulo m in the same way as A is given.
Sample Input
2 2 4
0 1 1 1Sample Output
1 2
2 3Solution
题目大意:给一个n*n矩阵A 和 系数k, 求 S=A+A2+A3+…+Ak 。 定义一个2n*2n的矩阵B,I为单位矩阵 Bn+1=∣∣∣A0II∣∣∣n+1=∣∣∣An0A+A2+A3+...+An+II∣∣∣
求 Bn+1取B[0][1]−I即可。 Code
include#include #include #include using namespace std;#define maxn 100typedef long long ll;struct Mat{ int mat[maxn][maxn];//矩阵 int row, col;//矩阵行列数 };Mat mod_mul(Mat a, Mat b, int p)//矩阵乘法 { Mat ans; ans.row = a.row; ans.col = b.col; memset(ans.mat, 0, sizeof(ans.mat)); for (int i = 1;i <= ans.row;i++) for (int j = 1;j <= ans.col;j++) for (int k = 1;k <= a.col;k++) { ans.mat[i][j] += a.mat[i][k] * b.mat[k][j]; ans.mat[i][j] %= p; } return ans;}Mat mod_pow(Mat a, int k, int p)//矩阵快速幂 { Mat ans; ans.row = a.row; ans.col = a.col; for (int i = 1;i <= a.row;i++) for (int j = 1;j <= a.col;j++) ans.mat[i][j] = (i == j); while (k) { if (k & 1)ans = mod_mul(ans, a, p); a = mod_mul(a, a, p); k >>= 1; } return ans;}int main(){ int n, m, k; while (~scanf("%d%d%d", &n, &k, &m)) { Mat A; A.row = A.col = 2 * n; memset(A.mat, 0, sizeof(A.mat)); for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++) scanf("%d", &A.mat[i][j]); for (int i = 1; i <= n; i++) A.mat[i][i + n] = A.mat[i + n][i + n] = 1;//初始化单位矩阵 Mat B = mod_pow(A, k + 1, m); for (int i = 1; i <= n; i++) for (int j = n+1; j <= 2*n; j++) { if (i + n == j) printf("%d", ((B.mat[i][j] - 1) % m+m)%m);//((B.mat[i][j] - 1) % m+m)%m 避免结果为负数 else printf("%d", B.mat[i][j]); printf("%c", j == 2 * n ? '\n' : ' '); } } return 0;}