基础篇-BASIC-17 VIP试题矩阵乘法（c++）

港控/mmm° 2022-12-13 11:26 160阅读 0赞

摘自百度百科：  
1、当矩阵A的列数（column）等于矩阵B的行数（row）时，A与B可以相乘。  
2、矩阵C的行数等于矩阵A的行数，C的列数等于B的列数。  
3、乘积C的第m行第n列的元素等于矩阵A的第m行的元素与矩阵B的第n列对应元素乘积之和。

#include <iostream>
    
    using namespace std;
    const int MAX_Order = 30 + 5;
    
    int Matrix_A[MAX_Order][MAX_Order], Matrix_res[MAX_Order][MAX_Order];
    int Matrix_temp[MAX_Order][MAX_Order];
    
    int main()
    {
        
        ios::sync_with_stdio(false);
        int N, M;
        cin >> N >> M;
        for (int i = 1; i <= N; i++)
            for (int j = 1; j <= N; j++)
            {
        
                cin >> Matrix_A[i][j];
                //A的一次幂放在Matrix_temp里
                Matrix_res[i][j] = Matrix_A[i][j];
                Matrix_temp[i][j] = Matrix_A[i][j];
            }
    
        for (int cnt = 1; cnt < M; cnt++)
        {
        
            for (int i = 1; i <= N; i++)
                for (int j = 1; j <= N; j++)
                {
        
                    Matrix_res[i][j] = 0;
                    for (int k = 1; k <= N; k++)
                    {
        
                        //cout << '[' << Matrix_temp[i][k]  << ", "<< Matrix_A[k][j] << ']' << endl;
                        Matrix_res[i][j] += Matrix_temp[i][k]  * Matrix_A[k][j];
                    }
                    //这句话会影响之后的计算，因为temp[][]的值被修改了
                    //Matrix_temp[i][j] = Matrix_res[i][j];
    
                }
            for (int i = 1; i <= N; i++)
                for (int j = 1; j <= N; j++)
                    Matrix_temp[i][j] = Matrix_res[i][j];
        }
        for (int i = 1; i <= N; i++)
        {
        
            for (int j = 1; j <= N; j++)
            {
        
                if (j != 1) cout << " ";
                cout << Matrix_res[i][j];   
            }
            cout << endl;
        }    
        system("pause");
        return 0;
    }