矩阵在竞赛中的应用

矩阵乘法代码：

struct matrix {int n, m;int a[100][100];
};
// A.m == B.n
matrix matrix_mul(matrix A, matrix B) {matrix C;C.n = A.n;C.m = B.m;for (int i = 0; i < A.n; ++i) {for (int j = 0; j < B.m; ++j) {C.a[i][j] = 0;for (int k = 0; k < A.m; ++k) {C.a[i][j] += A.a[i][k] * B.a[k][j];}}}return C;
}

下一节：矩阵二分快速幂优化dp