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 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[0].r, matrices[len(matrices)-1].c}, v
	}
	if len(matrices) == 0 {
		panic("must not be empty")
	} else if len(matrices) == 1 {
		return matrices[0], 0
	} else if len(matrices) == 2 {
		return calcMultiplication(matrices[0], matrices[1])
	}

	var minCount int = math.MaxInt32

	for i := 0; i < len(matrices)-1; i++ {
		formerMatrices := matrices[:i+1]
		latterMatrices := matrices[i+1:]
		matF, countF := calcMinMatrixChainMultiplication(formerMatrices, Range{0, i}, memo)
		matL, countL := calcMinMatrixChainMultiplication(latterMatrices, Range{i + 1, len(matrices) - 1}, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	return Matrix{matrices[0].r, matrices[len(matrices)-1].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++: ///
// File:  alds1_10_b.cpp
// Author: ymiyamoto
//
// Created on Tue Oct 17 21:37:26 2017
//

#include <cstdint>
#include <iostream>
#include <vector>

using namespace std;

static vector<uint32_t> matrix(101, 0);
static uint64_t dp[101][101];

int32_t main()
{
  uint32_t n;
  cin >> n;

  for (uint32_t i = 1; i <= n; i++) {
    cin >> matrix[i - 1] >> matrix[i];
  }

  for (uint32_t l = 2; l <= n; l++) {
    for (uint32_t i = 1; i <= n - l + 1; i++) {
      uint32_t j = i + l - 1;
      uint64_t min_val = UINT64_MAX;
      for (uint32_t k = i; k <= j - 1; k++) {
        min_val = min(min_val, dp[i][k] + dp[k + 1][j] + matrix[i - 1] * matrix[k] * matrix[j]);
      }
      dp[i][j] = min_val;
    }
  }

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

  return 0;
}

C++: #include <iostream>
#include <algorithm>
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<cstdio>
#define INT_MAX 100000000
using namespace std;
int index;
int mm[1000][1000];
int mine = INT_MAX;

void solve(int p[]){
  int n = index-1,j,q;
  for(int i=1;i<=n;i++)mm[i][i]=0;
  for(int l=2;l<=n;l++){
    for(int i=1;i<=n-l+1;i++){
      j = i+l-1;
      mm[i][j] = INT_MAX;
      for(int k=i;k<=j-1;k++){
	q = mm[i][k] + mm[k+1][j] + p[i-1]*p[k]*p[j];
	if(q<mm[i][j]){
	  mm[i][j] = q;
       
	}

      }
    }
  }




}

int main(){
  int p[1000],a,b;
  scanf("%d",&index);
  //for(int i=0;i<=index;i++)for(int j=0;j<=n;j++)mm[i][j] = INT_MAX;
  for(int i=0;i<index;i++){
    scanf("%d %d",&a,&b);
    p[i] = a;
    if(i == index-1)p[i+1] = b;
  }

  index = index+1;
  solve(p);
 
  printf("%d\n",mm[2][index-2]);
  return 0;
}

C++: // http://algorithms.blog55.fc2.com/blog-entry-66.html

#include <iostream>
using namespace std;
#include <stdio.h>

#define MAX 100
#define INFTY (1 << 21)

int SIZE;
int R[MAX + 2];
int C[MAX+1][MAX+1]; // cost table
int B[MAX+1][MAX+1]; // best table

void compute(){
    for ( int i = 0; i <= SIZE; i++ )
    for ( int j = 0; j <= SIZE; j++ ) C[i][j] = INFTY;
    
    for ( int i = 0; i <= SIZE; i++ ) C[i][i] = 0;
    
    for ( int j = 1; j <= SIZE - 1; j++ ){
        for ( int i = 0; i < SIZE - j; i++ ){
            for ( int k = i; k < i + j; k++ ){
                // C[i][i+j] = min( C[i][i+j], 
                //                  C[i][k-1] + C[k][i+j] + R[i]*R[k]*R[i+j+1]);
                int cost = C[i][k] + C[k+1][i+j] + R[i]*R[k+1]*R[i+j+1];
                if ( cost < C[i][i+j] ){
                    C[i][i+j] =  cost;
                    B[i][i+j] = k;
                }
                
            }
        }
    }
}

void order( int i, int j ){
    if ( i == j ) cout << "M" << i;
    else{
        cout << "(";
        order( i, B[i][j]-1 ); order(B[i][j], j);
        cout << ")";
    }
}

void input(){
    cin >> SIZE;
	int z,i=0;
    for (; i < SIZE; i++ ) cin >> R[i]>>z;
	R[i]=z;
	//SIZE++;
}

void output(){
    cout <<  C[0][SIZE-1] << endl;
    //order(1, SIZE);
    //cout << endl;
}

main(){
    input();
    compute();
    output();
}

C++: // Ref : https://book.mynavi.jp/ec/products/detail/id=35408

#include <iostream>
#include <algorithm>
#include <limits.h>
using namespace std;

static const int N = 100;;

int main() {
	int n; cin >> n;
	int p[N + 1], m[N + 1][N + 1]; // m_ij is partial LCS between i to j.
	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++) { // l is a length of partial LCS.
		for (int i = 1; i <= n - l + 1; i++) {
			int j = i + l - 1;
			m[i][j] = INT_MAX;
			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[j] * p[k]);
			}
		}
	}
	cout << m[1][n] << endl;

	return 0;
}

C++: #include <iostream>

using namespace std;

static const int MAX = 100;

class MatrixChainMultiplication {
private:
    int MCM[MAX + 1][MAX + 1];
    int p[MAX + 1];
    int n;

    void set()
    {
        cin >> n;
        cin >> p[0];
        int _;
        for(int i = 1; i <= n; i++)
        {
            cin >> p[i];
            if(i == n)
                break;
            cin >> _;
        }
    }

public:
    MatrixChainMultiplication()
    {
        set();
    }

    int matrix_chain_multiplication()
    {
        for(int i = 1; i <= n; i++)
            MCM[i][i] = 0;

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

        return MCM[1][n];
    }
};

int main()
{
    MatrixChainMultiplication mcm;
    cout << mcm.matrix_chain_multiplication() << endl;
}