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>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define INT_MAX 2147483647
#define INT_MIN -2147483646
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;

int memo[105][105];
int r[105], c[105];

int func(int a, int b) {
	if (memo[a][b] != INT_MIN) return memo[a][b];
	if (b - a == 0) { 
		memo[a][b] = 0;
	}
	else {
		int m = INT_MAX;
		for (int k = a;k < b;k++) {
			m = min(m, func(a, k) + func(k + 1, b) + r[a] * c[k] * c[b]);
		}
		memo[a][b] = m;
	}
	return memo[a][b];
}

int main() {
	int n;
	cin >> n;
	Loop(i, n) {
		Loop(j, n) {
			memo[i][j] = INT_MIN;
		}
	}
	Loop(i, n) {
		cin >> r[i] >> c[i];
	}
	cout << func(0, n - 1) << endl;
	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 "bits/stdc++.h"
using namespace std;
typedef long long ll;

template <typename TYPE>
void print_vec(const vector<TYPE>& v){
	for(int i=0; i<v.size(); i++){
		cout << v[i] << " ";
	}
	cout << endl;
}

template <typename TYPE>
void print_vec2(const vector<vector<TYPE>>& v){
  cout << endl; cout << "       ";
  for(int i=0; i<v[0].size(); i++) cout << i << "   "; 
  cout << endl;
	for(int i=0; i<v.size(); i++){
		cout << "i=" << i << ":   ";
		for(int j=0; j<v[i].size(); j++){
			if(v[i][j] == 0) cout << "\x1B[0m" << v[i][j] << "   ";
      else cout << "\x1B[31m" << v[i][j] << "   ";//https://stackoverrun.com/ja/q/12618775
		}
		cout << "\x1B[0m" << endl;
	}
}
 
ll chmin(ll &a, ll b) {return a = min(a, b);}

int main(){
	int n;
	cin >> n;
	vector<ll> row(n), col(n);// 計算に使うんでllにしときます
	for(int i=0; i<n; i++) cin >> row[i] >> col[i];
	const ll INF = 100100100100100;
	// dp[l][r]: 区間[l,r]の行列の積を計算するのに必要なスカラー乗算の最小回数 
	// ll ans = dp[0][n-1] となるよ
	vector<vector<ll>> dp(n+1, vector<ll>(n+1, INF));
	
	//初期化
	for(int l=0; l<n; l++){
		dp[l][l] = 0;//行列1つだけじゃあ計算回数は0
	}

	for(int w=1; w<n; w++){
		for(int l=0; l+w<n; l++){
			int r = l+w;
			for(int mid=l; mid<r; mid++){// 結合する位置をずらしていく
				ll num = row[l] * col[mid] * col[r];// a×b と b×c の計算回数は a * b * c
				num = row[l] * row[mid+1] * col[r];//こっちでもよい
				chmin(dp[l][r], dp[l][mid] + num + dp[mid+1][r]);// 例  a×b と b×c　と c×d　の計算回数は a*b*c + a*c*d 　と  b*c*d + a*b*d  の小さいほう 
			}
		}
	}

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

C++: #include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>

#define INF 100000001

using namespace std;

int DP[101][101];
int *p;

int rec(int r,int c){
    int Min = INF;
    int num = c - r;
    
    for (int i = 0; i < num; i++) {
        Min = min(Min , DP[r][r+i] + DP[r+i+1][c] + p[r-1]*p[r+i]*p[c]);
    }
    return Min;
}

int main(){
    int N;
    cin >> N;
    for (int i = 1; i <= N; i++) DP[i][i] = 0;
    
    p = (int *)malloc(sizeof(int)* (N+1));
    
    cin >> p[0];
    cin >> p[1];
    int bb;
    for (int i = 2; i <= N; i++) {
        cin >> bb;
        cin >> p[i];
    }
    
    for (int i = 1; i < N; i++) DP[i][i+1] = p[i-1]*p[i]*p[i+1];
    
    
    for (int j = 0; j <= N-3 ; j++) {//?????????????????????
        for (int i = 3+j; i <= N; i++) {//????????°???????????????
            DP[i-2-j][i] = rec(i-2-j,i);
        }
    }
    
    cout << DP[1][N] << endl;
    
    return 0;
}

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

void solve(){
  int n; cin >> n;
  vector<int> p(n + 1);
  for(int i = 0; i < n; i++){
    cin >> p[i] >> p[i + 1];
  }
  vector<vector<int> > m(n + 1, vector<int>(n + 1));
  for(int i = 1; i <= n; i++) m[i][i] = 0;
  for(int i = 2; i <= n; i++){
    for(int j = 1; j <= n - i + 1; j++){
      int t = 1000000000;
      for(int k = j; k <= j + i - 2; k++){
        t = min(m[j][k] + m[k + 1][j + i - 1] + p[j - 1] * p[k] * p[j + i - 1], t);
      }
      m[j][j + i - 1] = t;
    }
  }
  cout << m[1][n] << endl;
  return;
}

int main(){
  solve();
  return 0;
}

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

int c[100][100];

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, t;
    int M[101];
    cin>>n;
    cin>>M[0]>>M[1];
    for(int i=2; i<=n; i++) {
        cin>>t>>M[i];
    }
    for(int l=1; l<n; l++) {
        for(int i=0; i+l<n; i++) {
            int cost=numeric_limits<int>::max();
            for(int j=i+1; j<=i+l; j++) {
                cost=min(cost, c[i][j-1]+M[i]*M[j]*M[i+l+1]+c[j][i+l]);
            }
            c[i][i+l]=cost;
        }
    }
    cout<<c[0][n-1]<<'\n';
}

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

static const int N= 100;
int p[N+1], m[N+1][N+1];

int main() {
    ios::sync_with_stdio(false);
    int n;
    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++){ //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;
}