Go: package main

import (
	"bufio"
	"fmt"
	"math"
	"os"
	"strconv"
)

type Matrix struct {
	r int // num of row
	c int // num of column
}

type Range struct {
	start int // index, inclusive
	end   int // index, inclusive
}

func (r Range) length() int {
	return r.end - r.start + 1
}

func calcMultiplication(x, y Matrix) (Matrix, int) {
	if x.c != y.r {
		panic("cannnot calculate")
	}
	return Matrix{x.r, y.c}, x.r * y.c * x.c
}

func calcMinMatrixChainMultiplication(matrices []Matrix, r Range, memo map[Range]int) (Matrix, int) {
	if v, ok := memo[r]; ok {
		return Matrix{matrices[r.start].r, matrices[r.end].c}, v
	}
	if r.length() == 0 {
		panic("must not be empty")
	} else if r.length() == 1 {
		return matrices[r.start], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < r.length()-1; i++ {
		formerRange := Range{r.start, r.start + i}
		latterRange := Range{r.start + i + 1, r.end}
		matF, countF := calcMinMatrixChainMultiplication(matrices, formerRange, memo)
		matL, countL := calcMinMatrixChainMultiplication(matrices, latterRange, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[r.start].r, matrices[r.end].c}, minCount
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, _ := nextInt(sc)
	matrices := make([]Matrix, n)
	for i := 0; i < n; i++ {
		r, _ := nextInt(sc)
		c, _ := nextInt(sc)
		matrices[i] = Matrix{r, c}
	}
	memo := make(map[Range]int)
	_, resultCount := calcMinMatrixChainMultiplication(matrices, Range{0, len(matrices) - 1}, memo)
	fmt.Println(resultCount)
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include<bits/stdc++.h>
using namespace std;
#define INF 1000000000
#define mp make_pair
#define fi first
#define se second

int main()
{
    int n;cin >> n;
    vector<pair<int,int>> matrix(n);
    int a,b;
    for (int i=0;i<n;i++)
    {
        cin >> a >> b;
        matrix[i]=mp(a,b);
    }
    vector<vector<pair<int,pair<int,int>>>> dp(n,vector<pair<int,pair<int,int>>> (n,mp(INF,mp(-1,-1))));
    for (int i=0;i<n;i++)
    {
        dp[i][i].fi=0;
        dp[i][i].se.fi=matrix[i].fi;
        dp[i][i].se.se=matrix[i].se;
    }
    for (int len=1;len<n;len++)
    {
        for (int l=0;l<n-len;l++)
        {
            int r=l+len;
            //cout << l << r << endl;
            for (int m=l;m<r;m++)
            {
                if (dp[l][r].fi>dp[l][m].fi+dp[m+1][r].fi+dp[l][m].se.fi*dp[l][m].se.se*dp[m+1][r].se.se)
                {
                    //cout << l <<" " << r << ":" ;
                    dp[l][r].fi=dp[l][m].fi+dp[m+1][r].fi+dp[l][m].se.fi*dp[l][m].se.se*dp[m+1][r].se.se;
                    dp[l][r].se.fi=dp[l][m].se.fi;
                    dp[l][r].se.se=dp[m+1][r].se.se;
                    //cout << dp[l][r].fi<< endl;
                }
            }
        }
    }
    cout << dp[0][n-1].fi << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

constexpr int INF = 1e9;

int dp[110][110];

int main(){
  int n; cin >> n;
  int p[110];
  for( int i = 0; i < n; i++ ) cin >> p[i] >> p[i + 1];
  for( int i = 0; i < 110; i++ ){
    for( int j = 0; j < 110; j++ ){
      if( i != j ) dp[i][j] = INF;
    }
  }
  
  for( int l = 2; l <= n; l++ ){
    for( int i = 0; i < n - l + 1; i++ ){
      int j = l + i - 1;
      for( int k = i; k < j; k++ ){
	dp[i][j] = min( dp[i][j], dp[i][k] + dp[k + 1][j] + p[i] * p[k + 1] * p[j + 1] );
      }
    }
  }

  cout << dp[0][n - 1] << endl;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
#define INF 1<<30

static const int N = 100;

int main() {
    int n;
    int p[N+1], m[N+1][N+1];
    cin >> n;
    for (int i=1; i<=n; i++) {
        cin >> p[i-1] >> p[i];
    }

    for (int i=1; i<=n; i++) {
        m[i][i] = 0;
    }
    for (int l=2; l<=n; l++) {
        for (int i=1; i<=n-l+1; i++) {
            int j = i+l-1;
            m[i][j] = INF;
            for (int k=i; k<=j-1; k++) {
                m[i][j] = min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
            }
        }
    }

    cout << m[1][n] << endl;
    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

static const int N = 100;

int main() {
  int n, p[N+1], m[N+1][N+1];
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> p[i-1] >> p[i];
  }

  for (int i = 1; i <= n; i++) m[i][i] = 0;
  for (int l = 2; l <= n; l++) {
    for (int i = 1; i <= n-l+1; i++) {
      int j = i + l - 1;
      m[i][j] = (1<<21);
      for (int k = i; k <= j-1; k++) {
        m[i][j] = min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
      }
    }
  }

  cout << m[1][n] << endl;

  return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
#define N 100
int main() {
	int n, p[N + 1], m[N + 1][N + 1];
	cin >> n;
	for (int i = 1; i <= n; i++)cin >> p[i - 1] >> p[i];
	for (int i = 1; i <= n; i++)m[i][i] = 0;
	for (int l = 2; l <= n; l++) {
		for (int i = 1; i <= n - l + 1; i++) {
			int j = i + l - 1;
			m[i][j] = (1 << 21);
			for (int k = i; k <= j - 1; k++) {
				m[i][j] = min(m[i][j], m[i][k] + m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
			}
		}
	}
	cout << m[1][n] << endl;
	return 0;
}