PD Inmultirea optima de matrici

/*
intrare .txt
4
3 4 9 5 2
n=4 numarul de matrici; prima are dimensiunile (3,4) a doua (4,9) a treia (9,5), a 4-a (5,2)
*/


#include<iostream>
#include<cstdio>
#include<fstream>
#include<vector>
#include<limits>
#include<algorithm>
using namespace std;



int main() {
    int n, i, j, k;
    vector<int> P;
    int M[100][100];

    ifstream fin("intrare.txt");
    fin >> n;
    for (i = 0; i <= n; i++)
        for (j = 0; j <= n; j++)
            M[i][j] = 999;
    P.resize(n + 1);
    for (i = 0; i <= n; i++) fin >> P[i];
    fin.close();



    for (i = 1; i <= n; i++)
        M[i][i] = 0;


    for (int len = 1; len < n; len++)
        for (i = 1; i + len <= n; i++)
            for (k = i; k < i + len; k++)
                M[i][i + len] = min(M[i][i + len], M[i][k] + M[k + 1][i + len] + P[i - 1] * P[k] * P[i + len]);

    cout << M[1][n] << endl << endl; // costul inmultirii celor n matrici

    for (i = 1; i <= n; i++) {
        for (j = 1; j <= n; j++)
            printf("%3d ", M[i][j]);
        printf("\n");
    }

    system("PAUSE");
    return 0;
}