题解 | 矩阵乘法

#include <iostream>//----------还没学矩阵算法，不知道有没有更快的思路，我用的是模拟
#include <vector>
using namespace std;
#define pre(var, stare, end) for(int var = stare; var < end; var++)
int main() {
  int x, y, z;
  cin >> x >> y >> z;
  vector<vector<int>> a(x, vector<int>(y)), b(y, vector<int>(z)), ans(x, vector<int>(z));
  pre(i, 0, x)//读取A
    pre(j, 0, y)
      cin >> a[i][j];
  pre(i, 0, y)//读取B
    pre(j, 0, z)
      cin >> b[i][j];
  pre(i, 0, x)//生成答案
    pre(j, 0, z){
      int midans = 0;
      pre(k, 0, y)
        midans += a[i][k] * b[k][j];
      ans[i][j] = midans;
    }
  pre(i, 0, x){//输出
    pre(j, 0, z)
      cout << ans[i][j] << " ";
    cout << endl;
  }
}
// 64 位输出请用 printf("%lld")