因爲矩陣相乘是諸多算法中的基礎,就像乘法之於快速冪同樣,因此有必要熟練掌握,如下模板是我我的以爲用起來比較方便的,可是隨着時間遷移確定是須要對其進行精進的。ios
代碼示例:算法
struct Matrix{ int n,m; int v[maxn][maxn]; Matrix(int n,int m):n(n),m(m){} void init(){ //初始化矩陣 memset(v,0,sizeof v); } Matrix operator* (const Matrix B) const { Matrix C(n,B.m); //用來存放答案 C.init(); for(int i = 0;i < n;i++) for(int j = 0;j < B.m;j++) for(int k = 0;k < m;k++) C.v[i][j] += v[i][k]*B.v[k][j]; return C; } void print(){//輸出該矩陣,用來測試 for(int i = 0;i < n;i++){ for(int j = 0;j < m;j++) cout << v[i][j] << " "; cout << endl; } } };
也許須要完整代碼:測試
#include<iostream> #include<cstdio> #include<cstring> using namespace std; const int maxn = 105; struct Matrix{ int n,m; int v[maxn][maxn]; Matrix(int n,int m):n(n),m(m){} void init(){ //初始化矩陣 memset(v,0,sizeof v); } Matrix operator* (const Matrix B) const { Matrix C(n,B.m); //用來存放答案 C.init(); for(int i = 0;i < n;i++) for(int j = 0;j < B.m;j++) for(int k = 0;k < m;k++) C.v[i][j] += v[i][k]*B.v[k][j]; return C; } void print(){//輸出該矩陣,用來測試 for(int i = 0;i < n;i++){ for(int j = 0;j < m;j++) cout << v[i][j] << " "; cout << endl; } } }; int main(){ FILE *fp = fopen("Matrix.txt","r"); int n1,m1,n2,m2; fscanf(fp,"%d%d",&n1,&m1); Matrix A(n1,m1); for(int i = 0;i < n1;i++) for(int j = 0;j < m1;j++){ fscanf(fp,"%d",&A.v[i][j]); } fscanf(fp,"%d%d",&n2,&m2); Matrix B(n2,m2); for(int i = 0;i < n2;i++) for(int j = 0;j < m2;j++){ fscanf(fp,"%d",&B.v[i][j]); } Matrix C = A*B; C.print(); fclose(fp); return 0; }