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 <string>
#include <algorithm>
#include <vector>

using namespace std;
static const int N = 100;

#define INT_MIN     (-2147483647 - 1) /* minimum (signed) int value */
#define INT_MAX       2147483647    /* maximum (signed) int value */

void solve(vector<int> &data)
{
	vector<vector<int> > dp(N + 1, vector<int>(N + 1, 0));

	int nums = data.size() - 1;
	for (int len = 2; len <= nums; ++len)
	{
		for (int l = 1; l <= nums - len + 1; ++l)
		{
			int r = l + len - 1;
			dp[l][r] = INT_MAX;
			for (int m = l; m <= r - 1; ++m)
			{
				cout << len << " " << l << " " << r << endl;
				dp[l][r] = min(dp[l][r], dp[l][m] + dp[m+1][r] + data[l - 1] * data[m] * data[r]);
			}
		}
	}

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

int main()
{
	int num; cin >> num;
	vector<int> data(num + 1);
	for (int i = 1; i <= num; ++i)
		cin >> data[i-1] >> data[i];

	solve(data);
}

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

static const int maxn=44;

int DP[45];

int Fibonacci(int n) {
  if (n==0 or n==1) {
    return DP[n]=1;
  }
  if (DP[n]!=(-1)) {
    return DP[n];
  }
  return DP[n]=Fibonacci(n-1)+Fibonacci(n-2);
}
int main() {
  std::ios::sync_with_stdio(false);
  cout.tie(0);
  cin.tie(0);
  memset(DP,(-1),sizeof(DP));
  Fibonacci(maxn);
  int n;
  cin>>n;
  cout<<DP[n]<<endl;
  return 0;
}

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


int main()
{
    int n,p[101];
    cin>>n;
    for(int i=1;i<=n;i++)
        cin>>p[i-1]>>p[i];
    int m[100][100];
    for(int i=0;i<n;i++)
        m[i][i]=0;
    for(int len=2;len<=n;len++)
        for(int i=0;i<n-len+1;i++)
        {
            int j=i+len-1;
            m[i][j]=1<<20;
            for(int k=i;k<i+len-1;k++)
                m[i][j]=min(m[i][j],m[i][k]+m[k+1][j]+p[i]*p[k+1]*p[j+1]);
        }
    cout<<m[0][n-1]<<endl;
    return 0;

}

C++: #include <bits/stdc++.h>
using namespace std;

int main() {
  int n;
  cin >> n;
  
  vector<int> p(n + 1);
  for (int i = 0; i < n; i++) {
    cin >> p.at(i) >> p.at(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 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;
}

C++: #include <bits/stdc++.h>
//----***やべーやつら***----
using namespace std;
#define int long long

//----***型定義***----
using ll = long long;
using P = pair<int,int>;

//----***Like a Pythonista***----
#define REP(ii,jj,nn) for (ll ii=jj;ii<(nn);ii++)
#define RREP(ii,nn,jj) for (ll ii = nn; jj<ii;ii--)
#define each(i,...) for (auto&& i:__VA_ARGS__)
#define ALL(vec) (vec).begin(),(vec).end()
#define sum(...) accumulate(ALL(__VA_ARGS__),0LL)
#define dsum(...) accumulate(ALL(__VA_ARGS__),0.0)
#define vec(type,name,...) vector<type> name(__VA_ARGS__)
template<class T> inline auto max(const T& a){ return *max_element(ALL(a)); }
template<class T> inline auto min(const T& a){ return *min_element(ALL(a)); }
inline ll gcd(ll a,ll b){if(b == 0) return a;return  gcd(b,a%b);}
inline ll lcm(ll a,ll b){ll g = gcd(a,b);return a / g * b;}

//----***定数***----
#define MOD 1000000007
#define INF 100000000000000000
#define EPS 1e-9
const vector<vector<int>> DXY={{-1,0},{1,0},{0,-1},{0,1}};

//----***パーツ***----
#define fr first
#define se second
#define pb push_back

//----***入出力***---
#define print(out) cout<< out  << "\n";
#define debug(var)  do{std::cerr << #var << " ↓ "<<"\n";view(var);}while(0);
#define dbg cerr<<"🥺🥺🥺🥺🥺🥺"<<endl;
template<typename T> void view(T e){std::cout << e << std::endl;}
template<typename T> void view(const std::vector<T>& v){for(const auto& e : v){ std::cout << e << " "; } std::cout << std::endl;}
template<typename T> void view(const std::vector<std::vector<T> >& vv){ for(const auto& v : vv){ view(v); } }

//----***初期時読み込み***----
struct initial{initial(){cin.tie(0); ios::sync_with_stdio(0); cout<<fixed<<setprecision(15);};}initial_;

vector<vector<int>>dp(30,vector<int>(500,0));

signed main(){
  int N;cin>>N;
  vector<P> M(N);
  REP(i,0,N)cin>>M[i].fr>>M[i].se;
  vector<vector<int>> dp(N+1,vector<int>(N+1,INF));
  REP(i,0,N+1)dp[i][i]=0;

  REP(w,1,N)REP(i,0,N-w){
    int j=i+w;
    REP(k,i,j){
        int prod=M[i].fr*M[k].se*M[j].se;
        dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]+prod);
    }
  }
  print(dp[0][N-1])
}

C++: #include<stdio.h>

int matrixChainOrder(int *p);
int m[101][101];
int n1;
int main(){
  
  int i,r,c,min;
  int p[100];
  scanf("%d",&n1);

  for(i=0;i<n1;i++){
    scanf("%d %d",&r,&c);
    if(i==n1-1) p[n1]=c;
    p[i]=r;
  }

  min = matrixChainOrder(p);
  printf("%d\n",min);

  return 0;
}

int matrixChainOrder(int *p){
  int n2,l,i,j,q,k;
  
  n2 = n1 - 1;
  for(i=1;i<=n2;i++){
    m[i][i] = 0;
  }
  for(l=2;l<=n2;l++){ 
    for(i=1;i<=n2-l+1;i++){ 
      j = i+l-1;
      m[i][j] = 1.0/0.0;
      for(k=i;k<j;k++){
	q = m[i][k] + m[k+1][j]+p[i-1]*p[k]*p[j];
        if(m[i][j]>=q)  m[i][j] = q;
      }
    }
  }
  return m[i][j];
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <math.h>
#include <cmath>
#include <string>
#include <cstdio>
using namespace std;
typedef long long int ll;
static int const 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 i = 2; i <= n; i++) {
		for (int j = 1; j <= n - i + 1; j++) {
			int k = j + i - 1;
			M[j][k] = (1 << 21);
			for (int l = j; l <= k - 1; l++) {
				M[j][k] = min(M[j][k], M[j][l] + M[l+1][k] + P[j - 1] * P[l] * P[k]);
			}
		}
	}
	cout << M[1][n] << endl;
}