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<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<bits/stdc++.h>
using namespace std;

int main(){
  int n,p[101],m[101][101];
  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+1;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++: // matrix chain multiplication
#include<iostream>
#define MAX 2000000
void MatrixChainMultiplication(int*,int);
int **F;
int main(){
  int n,i,j,*matrix;
  std::cin >> n;
  matrix = new int[n+1];
  F = new int*[n+1];
  for(i=1; i<=n; i++) F[i] = new int[n+1];
  for(i=0; i<n; i++){
    std::cin >> matrix[i] >> (i != n - 1 ? j : matrix[i+1]);
  }
  MatrixChainMultiplication(matrix,n);
  std::cout << F[1][n] << "\n";
  return 0;
}

void MatrixChainMultiplication(int* p,int n){
  int i,j,k,l,q;
  for(i=1; i<=n; i++) F[i][i] = 0;
  for(l=2; l<=n; l++){
    for(i=1; i<=n-l+1; i++){
      j = i + l - 1;
      F[i][j] = MAX;
      for(k=i; k<=j-1; k++){
        q = F[i][k] + F[k+1][j] + p[i-1] * p[k] * p[j];
        F[i][j] = (F[i][j] < q ? F[i][j] : q);
      }
    }
  }
}

C++: #include<stdio.h>
#define N 100
#define INF 9999999

int m[N][N], p[N], n;

void matrixChainOrder(){

  int i, j, k, l, q;

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

int main(){

  int  a, i;

  scanf("%d", &n);
  for(i = 0 ; i < n ; i++){
    scanf("%d%d", &p[i], &p[i+1]);
  }

  matrixChainOrder();
  
  printf("%d\n", m[1][n]);  

  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 <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int INF=(1<<21);

int n;
int dp[105][105], p[105];

void matrixChainMultiplication(){
    for(int i=1; i<=n; i++) dp[i][i]=0;

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

int main(void){
    cin >> n;
    for(int i=0; i<n; i++){
        int a,b; cin >> a >> b;
        if(i==0){
            p[0]=a, p[1]=b;
        }
        else p[i+1]=b;
    }

    matrixChainMultiplication();

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

C++: #include <cstdio>
#include <iostream>
using namespace std;

const int N=100;

int main(){
	int n;
	long m[N+1][N+1], p[N+1];
	
	scanf(" %d", &n);
	for(int i=1; i<=n; ++i)
		scanf(" %ld %ld", &p[i-1], &p[i]);
		
	for(int i=1; i<=n; ++i) m[i][i]=0;
	
	for(int s=2; s<=n; ++s){
		for(int i=1; i+s-1<=n; i++){
			int j=i+s-1;
			m[i][j]=100000000;
			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]);
			}
		}
	}
	
	printf("%ld\n", m[1][n]);
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

#define INF (100 * 100 * 100 * 100)

int n;
int m[110][110]; //minimum cost multiply matrixes from i to j

void matrixChainOrder(int *p){
  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;
      //search the minimun cost multiply matrixes from i to j
      for(int k = i;k <= j - 1;k++){
        int q = m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j];
        m[i][j] = min(m[i][j], q);
      }
    }
  }
}

int main(){
  
  int p[110];

  //input
  cin >> n;
  
  for(int i = 0;i < n;i++){
    int r, c;

    //p[0] is the number of first matrix's row
    //p[i] is the number of matrixs' column
    cin >> r >> c;
    if(i) p[i + 1] = c;
    else{
      p[0] = r;
      p[1] = c;
    }
  }
  
  matrixChainOrder(p);

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