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 <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <string>
#include <vector>

// Acknowledgement: Special thanks to kyomukyomupurin, who developed this
// template.
template <class T, class U>
std::ostream& operator<<(std::ostream& os, const std::pair<T, U>& p) {
  return os << '(' << p.first << ", " << p.second << ')';
}

template <class T>
std::ostream& operator<<(std::ostream& os, const std::vector<T>& vec) {
  int n = 0;
  for (auto e : vec) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T>
std::ostream& operator<<(std::ostream& os, const std::set<T>& st) {
  int n = 0;
  for (auto e : st) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T, class U>
std::ostream& operator<<(std::ostream& os, const std::map<T, U>& mp) {
  int n = 0;
  for (auto e : mp) os << (n++ ? ", " : "{") << e;
  return os << (n ? "}" : "{}");
}

template <class T>
std::istream& operator>>(std::istream& is, std::vector<T>& vec) {
  for (T& e : vec) is >> e;
  return is;
}

#ifdef LOCAL
#define debug(...) \
  std::cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

void debug_out() { std::cerr << '\n'; }

template <class Head, class... Tail>
void debug_out(Head&& head, Tail&&... tail) {
  std::cerr << head;
  if (sizeof...(Tail) != 0) std::cerr << ", ";
  debug_out(std::forward<Tail>(tail)...);
}
using namespace std;
using int64 = long long;

int main() {
  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>> dp(n + 1, vector<int>(n + 1));
  for (int l = 2; l <= n; l++) {
    for (int i = 1; i <= n - l + 1; i++) {
      int j = i + l - 1;
      if (i == j)
        dp[i][j] = 0;
      else {
        int tmp = 1e9;
        for (int k = i; k < j; k++) {
          tmp = min(tmp, dp[i][k] + dp[k + 1][j] + p[i - 1] * p[k] * p[j]);
        }
        dp[i][j] = tmp;
      }
    }
  }
  debug(dp);
  cout << dp[1][n] << endl;
  return 0;
}

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

const int INF = 1 << 28;

int main()
{
    int n;
    int dp[101][101];
    int r[102];
    
    cin >> n;
    
    fill((int*)dp, (int*)(dp + n), INF);
    
    for(int i = 0; i < n; ++i){
        cin >> r[i] >> r[i + 1];
        dp[i][i] = 0;
    }
    
    for(int w = 1; w < n; ++w){
        for(int i = 0, j ; j = i + w, j < n; ++i){
            for(int k = i; k < j; ++k){
                dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] + r[i] * r[k + 1] * r[j + 1]);
            }
        }
    }
    
    cout << dp[0][n-1] << endl;
    
}

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

void MatrixChainMultiplication(int n,int p[],int m[101][101]) {
	int i, j, k,l;
	for (i = 1; i <= n; i++) m[i][i] = 0;
	for (l = 2; l <= n; l++) {
		for (i = 1; i <= n - l +1; i++) {
			j = i + l - 1;
			m[i][j] = (1<<21);
			for (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]);
			}
		}
	}
}

int main() {
	int n, p[101], m[101][101];
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> p[i - 1] >> p[i];
	MatrixChainMultiplication(n, p, m);
	cout << m[1][n] << endl;

	
}

C++: #include <bits/stdc++.h>
#define INF 1e7

using namespace std;
typedef long long int ll;

int main()
{
    int n;
    cin >> n;
    vector<int>l(n),r(n);
    for(int i = 0; i < n; i++) cin >> l[i] >> r[i];
    vector<vector<int>>dp(n,vector<int>(n,INF));
    for(int i = 0; i < n; i++) dp[i][i] = 0;
    for(int p = 2; p <= n; p++)
    {
        for(int i = 0; i+p-1 <= n-1; i++)
        {
            int j = i+p-1;
            int S = INF;
            for(int k = i; k < j; k++) S = min(S,dp[i][k]+dp[k+1][j]+l[i]*r[k]*r[j]);
            dp[i][j] = S;
        }
    }
    cout << dp[0][n-1] << endl;
}

C++: #include <bits/stdc++.h>
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]m[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;
}