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

struct mat {
	int r, c;
	
	mat(int rv,int cv)
		:r{ rv }, c{ cv }{}
	mat() :r{}, c{} {}
	friend auto
		operator >> (std::istream&is, mat& m)->std::istream& {
		return
			is >> m.r >> m.c;
	}
};


using ui = unsigned int;
int main() {

	/*
	for (int l{ 2 }; l < 6; ++l) {

		for (int i{ 1 }; i < 6 - l + 1; ++i) {

			int j = i + l - 1;
			std::cout << "[ i, j ] = ( " << i << ", " << j << " ) >> k:";

			for (int k = i; k < j ; ++k)
				std::cout << " " << k;
			
			std::cout << "\n";
		}
		std::cout << std::endl;
	}*/
	

	int n;
	std::cin >> n;


	using ull = unsigned long long;
	using vu_t = std::vector<ull>;
	std::vector<vu_t> tab( n+1, vu_t(n+1, 0) );

	std::vector<mat> mv(n);
	for (auto&e : mv)
		std::cin >> e;

	
//	for (int i{}; i < n - 1; ++i) {
//		tab[i][i + 1] = mv[i].r * mv[i].c * mv[i + 1].c;
	//	std::cout << tab[i][i + 1] << " ";
//	}
	//std::cout << "\n";
	

	
	
	for (int l{ 2 }; l <= n; ++l) {
		for (int i{ 1 }; i <= n - l + 1; ++i) {
			ull t = (1 << 21);
			auto j = i + l - 1;
			for (int k{ i }; k <= j-1; ++k) {

				auto tt = tab[i][k] + tab[k + 1][j];
				auto c = mv[i-1].r * mv[k-1].c * mv[j-1].c;
				//std::cout << tt + c << "\t=\t" << tt << " + " << c << "\n";
				//std::cout << i << " " << k << " " << j << "\n";
				t = std::min(tt + c, t);
			}
			tab[i][j] = t;
		}
	}


//	for (const auto& e : tab) {
//		for (const auto&ee : e) {
//			std::cout << ee << "\t";
//		}std::cout << "\n";
//	}

//	put();
	std::cout << tab[1][n] << "\n";
	return 0;
}

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+=2) 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; 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 <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<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<<50);
for(int k = i;k<=j-1;k++){
m[i][j]=min(m[i][j],m[i][k]+m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
}
}
}
cout << m[1][n]<< endl;

return 0;

}

C++: #include<iostream>
#include<cstdio>
#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-1+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]);
      }
    }
  }
  printf("%d\n",m[1][n]);
  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<n;i++)
//#define int long long
using namespace std;

void print_vi(vector<int> vi)
{
	rep(i, vi.size())
	{
		printf("%d ", vi[i]);
	}
}

static const int N = 100;

signed 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;
}

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

typedef pair<int, int> pii;

int main(int argc, char *argv[]){
  int n;
  cin >> n;
  pii mat[n];
  int dp[n][n];
  int p[n + 1];

  //????????????
  for (int i = 0; i < n; i++) {
    cin >> mat[i].first >> mat[i].second;
  }
  for (int i = 0; i < n; i++) {
    p[i] = mat[i].first;
  }
  p[n] = mat[n - 1].second;
  for (int i = 0; i < n; i++) {
    for (int j = i; j < n; j++) {
      if(i != j)dp[i][j] = 1e9;
      else dp[i][j] = 0;
    }
  }
  //???????????§?????????
  //????????????DP
  for (int l = 2; l <= n; l++) {
    for (int i = 0; i <= n - l; i++) {
      int j = i + l - 1;
      for (int k = i; k < j; k++) {
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] +
                       p[i]*p[k + 1]*p[j + 1]);
      }
    }
  }
  std::cout << dp[0][n - 1] << std::endl;
            
  return 0;
}

C++: #include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
#include <cstring>
#include <deque>
#include <iomanip>
#include <limits>
#include <fstream>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
#define CLR(mat) memset(mat, 0, sizeof(mat))
typedef long long ll;
ll memo[111][111];
int n, a[111], b[111];
ll rec(int l, int r){
    if(memo[l][r] != 1e9) return memo[l][r];
    if(l == r) return memo[l][r] = 0;
    ll ret = 1e9;
    FOR(m, l, r){
      ret = min(ret, rec(l, m) + rec(m + 1, r) + a[l] * b[m] * b[r]);
    }
    return memo[l][r] = ret;
}
int main()
{
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  FOR(i,0,n) cin >> a[i] >> b[i];
  FOR(i,0,111)FOR(j,0,111)memo[i][j]=1e9;
  cout << rec(0,n-1) << endl;
}