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 "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

//#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }

int R[101], C[101];
int dp[101][101];

int f(int l, int r) {
	dump(l, r);
	if (dp[l][r] != INF)return dp[l][r];
	if (l >= r - 1)return 0;
	rep(m, l + 1, r) {
		chmin(dp[l][r], f(l, m) + f(m, r) + R[l] * R[m] * C[r - 1]);
	}
	return dp[l][r];
}

signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int n; cin >> n;
	rep(i, 0, n)cin >> R[i] >> C[i];
	memset(dp, 0x3f, sizeof(dp));
	cout << f(0, n) << endl;
	return 0;
}

C++: #include "bits/stdc++.h"
#include "math.h"
 
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<int> vin;
typedef pair<ll,ll> P;
typedef vector<P> vp;
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define drep(i,a,b) for(ll i=(a);i>=(b);--i)
#define SIZE(a) int((a).size())
#define out(a) cout<<(a)<<endl;
const int INF=INT_MAX;
const int MAX = 510000;
const ll MOD = 1000000007;
ll fac[MAX], finv[MAX], inv[MAX];

int main(){
  ll n;cin>>n;
  vll p(n+1);
  vvll dp(n,vll(n,MOD));
  rep(i,0,n){
    cin>>p[i]>>p[i+1];
  }
  rep(i,0,n){
    dp[i][i]=0;
  }
  rep(haba,0,n){
    rep(i,0,n-haba){
      int j=i+haba;
      rep(k,i,j){
        dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]+p[i]*p[k+1]*p[j+1]);
      }
    }
  }
  cout<<dp[0][n-1]<<endl;
}

C++: #include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <set>
#include <algorithm>
#include <array>
#include <complex>
#include <utility>
#include <map>
int needleX[4] = { -1,0,1,0 };
int needleY[4] = { 0,1,0,-1 };

int main(void) {
    int n;

    std::cin >> n;
    std::vector<int> p(100+1);
    for (int i = 1; i <= n; i++) {
        std::cin >> p[i-1] >> p[i];
    }
    int m[100 + 1][100 + 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] = std::min(m[i][j],  m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
            }
        }
    }
    /*for (int i = 1; i <= n; i++) {
        for (int j = i+1; j <= n; j++) {
            std::cout << m[i][j] << " ";
        }
        std::cout << std::endl;
    }*/
    std::cout << m[1][n] << std::endl;
    return 0;
}

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

long long int n, mat[100+1][100+1], len[100+1];

int main(void){
  int i, j, k, l;

  scanf("%d", &n);
  
  for(int i=1; i<=n; i++){
    scanf("%d %d", &len[i-1], &len[i]);
  }
  
  for(l=2; l<=n; l++){
    for(i=1; i<=n-l+1; i++){
      j=i+l-1;
      mat[i][j]=INT_MAX;

      for(k=i; k<=j-1; k++){
	mat[i][j]=min(mat[i][j], mat[i][k]+mat[k+1][j]+len[i-1]*len[k]*len[j]);
      }
    }
  }

  printf("%d\n", mat[1][n]);
  
  return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <string>
#include <cctype>
#include <stack>
#include <queue>
#include <vector>
#include <cstdlib>
#include <list>
#define _USE_MATH_DEFINES
#include <math.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];
		m[i][i] = 0;
	}

	for (int i = 2; i <= n; i++) {
		for (int j = 1; j <= n - i; j++) {
			int k = i + j - 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;

	return 0;
}

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

#define N 100

int M[101][101], p[101], n;

int solve()
{
	int l, i, j, k;
	for (l = 2; l <= n; l++) {
		for (i = 1; i <= n - l + 1; i++) {
			j = i + l - 1;
			M[i][j] = INT32_MAX;
			for (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]);
		}
	}
	return M[1][n];
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);

	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;

	cout << solve() << endl;
	return 0;
}

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

const int N = 102;

long m[N][N], p[N+1];

int matrixChainOrder(int n){

  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] = std::numeric_limits<long>::max();
      for(int k=i; k<=j-1; k++){
        m[i][j] = std::min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
      }
    }
  }
  return m[1][n - 1];
}

int main(){
  int n ;
  std::cin >> n; //number of matrix

  for(int i=1; i<=n; i++){
    std::cin >> p[i-1] >> p[i];
  }
  // for (int i = 0; i <=n; ++i) std::cout << p[i] << std::endl;
  std::cout << matrixChainOrder(n + 1) << std::endl;

  return 0;
}

C++: #include <iostream>
#include <cstdlib>
#include <string>
#include <typeinfo>
#include <cstring>
#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;
}