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
	}

	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
		}
	}
	memo[r] = minCount
	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++: #include <bits/stdc++.h>

#define REP(i, s, n) for (int i = s; i < n; i++)
#define rep(i, n) REP(i, 0, n)

using namespace std;

// data
const int MAX_N = 100;
int A[MAX_N][2]; // 0-col, 1-row
enum
{
    row, col
};

// dp
int dp[MAX_N+1][MAX_N]; // k number from A_i;
const int INF = 1 << 29;

int main(){
    int n; cin >> n;
    rep(i, n){
        cin >> A[i][row] >> A[i][col];
    }

    rep(k, n+1){
        rep(i, n){
            if (k <= 1)
                dp[k][i] = 0;
            else    
                dp[k][i] = INF;
        }
    }

    rep(k, n+1){
        rep(i, n){
            rep(j, k)
                dp[k][i] = min(dp[k][i], 
                    dp[j][i] + dp[k-j][i+j] + A[i][row]*A[i+j][row]*A[i+k-1][col]);
        }
    }

    cout << dp[n][0] << 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=0; i<=n; ++i) printf("p[%d]=%ld\n", i, p[i]);
		
	for(int i=1; i<=n; ++i) m[i][i]=0;
	
	for(int s=2; s<=n; ++s){ //s??????????????????
		for(int i=1; i+s-1<=n; ++i){ //?§????i
			int j=i+s-1; //??????j
			m[i][j]=100000000; //????????§???????????§?????????
			for(int k=i; k<=j-1; ++k){ //?????????k
				m[i][j]=min(m[i][j], m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
				//printf("go %d %d %d\n",i, j, k);
			}
		}
	}
	
	printf("%ld\n", m[1][n]);
}

C++: // Chain matrix multiplication (DP)

#include <algorithm>
#include <iostream>
#include <limits>
#include <vector>

using namespace std;
int main() {
  int n;
  cin >> n;

  int a, b;
  vector<int> A, B;
  while (cin >> a >> b) {
    A.push_back(a);
    B.push_back(b);
  }

  int cost[n][n];
  for (int i = 0; i < n; ++i) {
    for (int j = 0; j < n; ++j) {
      cost[i][j] = 0;
    }
  }

  // len=0 => cost = 0, the default value
  for (int len = 1; len < n; ++len) {
    for (int i = 0; i < n - len; ++i) {
      int j = i + len;
      int best = numeric_limits<int>::max();
      for (int k = i; k < j; ++k) {
        best = min(best, cost[i][k] + cost[k + 1][j] + A[i] * B[k] * B[j]);
      }
      cost[i][j] = best;
    }
  }

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

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;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)

struct Matrix {
  int low;
  int col;
};

int main() {
  int n; cin >> n;
  vector<Matrix> l(n);
  rep(i, n) {
    int a, b; cin >> a >> b;
    l.at(i).low = a;
    l.at(i).col = b;
  }

  vector<vector<int>> dp(n, vector<int>(n));
  rep(i, n) {
    dp.at(i).at(i) = 0;
  }

  for (int j = 1; j<n; j++) {
    int i = j-1;
    while (i>=0) {
      int k = i;
      int mi = 100000000;
      while (k < j) {
        mi = min(mi, (l.at(i).low * l.at(k).col * l.at(j).col) + dp.at(i).at(k) + dp.at(k+1).at(j));
        k++;
      }
      dp.at(i).at(j) = mi;
      i--;
    }
  }
  cout << dp.at(0).at(n-1) << endl;
}

C++: #include<stdio.h>
#include<cstdlib>

#define INF 2147483647

int n;

void P(){
  printf("\ntest\n");
}

int min(int a, int b){
  return a < b ? a : b;
}

int matrixChainOrder(int *P, int p, int l){
  int i, j, k, m[100][100], q;
  for(i = 1; i < n+1; i++){
    m[i][i] = 0;
  }
  for(i = 1; i < n; i++){ // tonaridousi de keisan
    m[i][i+1] = P[i-1] * P[i] * P[i+1];
  }
  for(i = 2; i <= n-1; i++){ // habahirogeru
    for(j = 1; j+i <= n; j++){ // dokokarahajimerukakimeru
      q = INF;
      for(k = 0; k < i; k++){
	q = min(q, m[j][j+k] + m[j+k+1][j+i] + P[j-1] * P[j+k] * P[j+i]);
	//printf("i:%d j:%d k:%d\n", i, j, k);
      }
      m[j][j+i] = q;
    }
  }

  return m[p][l];
}

int main(){
  int i, *P;

  scanf("%d", &n);
  P = (int *)malloc(sizeof(int) * n + 1);
  for(i = 0; i < n; i++){
    scanf("%d %d", &P[i], &P[i+1]);
  }

  printf("%d\n" ,matrixChainOrder(P, 1, n));

  return 0;
}

C++: #include <vector>
#include <iostream>
#include <string>
#include <climits>

class M{
  int left, right;
  int cnt;
public:
  M(int l = 0, int r = 0, int c = 0):left(l),right(r),cnt(c){}
  const bool is_init(){return left != 0;}
  int get_l(){return left;}
  int get_r(){return right;}
  int get_c(){return cnt;}
  void show(){std::cout << "[ " << left << "," << cnt << "," << right << " ]";}
  M operator+(M &other){
	  M res(left, other.get_r(), cnt + other.get_c() + left * right * other.get_r());
    return res;
  }
  bool operator>(M &other){
	  return cnt > other.get_c();
  }
};
void show_line(int line){
  std::cout << "start dp line " << line << std::endl;
}
void show_all(std::vector<M> &vec){
  for (auto i = vec.begin(); i != vec.end(); ++i){
    i->show();
    std::cout << "-";
  }
  std::cout << std::endl;
}
M Max(0, 0, INT_MAX);
int dp(std::vector<std::vector<M>> memo){
  if (memo.back().size() != 1){
  	std::vector<M> vec;
  	const int n = memo[0].size() - memo.size();
  	for (auto i = 0; i < n; ++i){
      M min = Max;
  		for (auto j = 0; j < memo.size(); ++j){
  			M temp = memo.at(j).at(i) + memo.at(memo.size() - j - 1).at(i + j + 1);
  			if (min > temp){
  				min = temp;
  			}
  		}
  		vec.push_back(min);
  	}
  	memo.push_back(vec);
  	return dp(memo);
	}else{
    return memo.back().back().get_c();
  }
}
int main(){
  int n;
  std::vector<M> v;
  std::cin >> n;
  for (auto i = 0; i < n; ++i){
	  int a, b;
	  std::cin >> a >> b;
	  v.push_back(M(a, b));
  }
  std::vector<std::vector<M>> memo;
  memo.push_back(v);
  std::cout << dp(memo) << std::endl;
  return 0;

}