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> // next_permutation
#include <iomanip>
#include <cmath>
#include <vector>
#include <sstream>
#include <string>
#include <cstdio>
#include <stack>
#include <queue>
#include <list>
#include <numeric> //accumulate
//#include <unordered_map> //???????????\??¢??°
#include <fstream> //ifstream, ofstream

//#define NDEBUG //NDEBUG???#include <cassert>???????????????????????????????????´???assert?????????????????????????????????NDEBUG?????????????????????????????????????????????
#include <cassert> //assert


using namespace std;

//???????????°??????TEST????????????????????¬???????????????????????????????????¢????????????
#define TEST //*******************************************************************************************************************************************
//?????????????????¨??§?????\????????????????????????????????°?????????????¨???????????????????dout???????????????????????§???????????¬??????????????????????????????????????????
//??????????????????????????????????????????????????????????§?CPU???????£??????????????????§???TLE?????????????????????????????????????????§????????¨???                           ????????????????????????cerr????????£????????????????????????????????????
#ifdef TEST
#define dout cout
#define din cin
#else
stringstream dummy; //???????????°??????dout?????????????????????????????????
#define dout dummy.str(""); dummy.clear(stringstream::goodbit); dummy //dummy?????????????????????????????????????????¨?????¢?????¢???????????????
//???????????¨??????????????????goodbit?????????????????????????????¨???????????´????????????????????????????????¨?????°?????????????????§???????????????????????????????????? http://d.hatena.ne.jp/linden/20060427/p1
#endif

//?¨??????????????????????????????????????????????????????´??????OUTPUTFILE????????????????????¬???????????????????????????????????¢????????????
//#define OUTPUTFILE "output.txt" //*******************************************************************************************************************************************
#ifdef OUTPUTFILE
#define dout outputfile //??¨????????????TLE????????§?????????dout?????¨??¨??????????????¢????????????????????????????????????????????§????¨????????????´??????????????£??????????????????????¨?????????????????????????????????????????????§?????????????????????
ofstream outputfile(OUTPUTFILE);
#define OutputFilePath "/Users/Nag/Documents/Prgm/Test/DerivedData/Test/Build/Products/Debug/output.txt"
#endif

//?¨??????\???????????????????????????????????????????????´??????INPUTFROMTEXTFILE????????????????????¬???????????????????????????????????¢????????????
//#define INPUTFILE "input.txt" //*******************************************************************************************************************************************
#ifdef INPUTFILE
#define din inputfile
ifstream inputfile(INPUTFILE);
#endif


#define disp(A) dout << #A << " = " << (A) << endl
#define disP(A) dout << setw(3) << (A) << " " // << setw(3) ??????????????\????????????
#define rep(i,a,n) for(int (i)=(a); (i)<(n); (i)++)

#define dispAll(A,n) dout << #A << " = "; rep(j, 0, (n)) {disP(A[j]);} dout << endl

typedef pair<int,int> pii;
typedef vector<int> vi;
typedef unsigned long long ll;

const int INF = 1e9-1;

int N;
int R[101];
int C[101];

int solve(int n, int r[], int c[]) {
    if(n==1) return 0;
    
    if(n==2) {
        assert(c[0]==r[1]);
        return r[0]*c[0]*c[1];
    }
    
    int min = INF;
    int tmp;
    rep(i,0,n-1) {
        
        //M[i]*M[i+1]?????????????????¨??????r[],c[]?????????
        int rr[n-1], cc[n-1];
        rep(j,0,n-1) {
            if(j<i) {
                rr[j] = r[j];
                cc[j] = c[j];
            }
            else if(j==i) {
                rr[j] = r[i];
                cc[j] = c[i+1];
            }
            else {
                rr[j] = r[j+1];
                cc[j] = c[j+1];
            }
        }
        
        //M[i]*M[i+1]?????????????´???°???1????????£???n-1??¨?????£?????????????????°???????§£???
        //????????????ans???M[i]*M[i+1]????¨?????????°??????????????????
        assert(c[i]==r[i+1]);
        tmp = solve(n-1, rr, cc) + r[i]*c[i]*c[i+1];
        
        if(tmp<min) min = tmp;
    }
    
    assert(min!=INF);
    return min;
}


int main() {
    din >> N;
    rep(i,0,N) {
        din >> R[i] >> C[i];
    }
    
    dout << solve(N, R, C) << endl;
    
    
#ifdef INPUTFILE
    inputfile.close();
#endif
    
#ifdef OUTPUTFILE
    outputfile.close();
    cout << "\"" << OutputFilePath << "\"" << endl;
#endif
    
    return 0;
}

C++: #include<iostream>
#include<stdio.h>
#include<stdlib.h>

using namespace std;

int minana(int a,int b){
  if(a<b){
    return a;
  }
  else if(a>b){
    return b;
  }
  else return a;
}


int main(){
  int n;
  cin>>n;
  int r[100];
  int m[101][101];
  int j;
  int q=0;
  //int c[n];
  for(int i=1;i<=n;i++){
    cin>>r[i-1]>>r[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++){
      j=i+l-1;
      m[i][j]=(1<<21);
      for(int k=i;k<j;k++){
	q=m[i][k]+m[k+1][j]+r[i-1]*r[k]*r[j];
	m[i][j]=minana(m[i][j],q);
      }
    }
  }
  
  cout<<m[1][n]<<endl;
  return 0;
}

C++: #include<iostream>
#include<cstdio>
#include<algorithm>
#define INFTY 1 << 21
using namespace std;

static const int N = 100;

int main(){
    int n;
    cin >> n;
    int p[N+1], m[N+1][N+1];
    for(int i = 1; i <= n; i++){
        scanf("%d %d", &p[i-1], &p[i]);
    }
    int i, j, l;
    for(i = 1; i <= n; i++){
        m[i][i] = 0;
    }   // 初期化
    for(l = 2; l <= n; l++){
        for(i = 1; i <= n - l + 1; i++){
            j = i + l - 1;
            m[i][j] = INFTY;
            for(int k = i; k < j; 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;
}