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 <cmath>
#include <deque>
#include <functional>
#include <iomanip>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
using ll = long long;
#define rep(i, n) for (int i = 0; i < n; i++)
#define repk(i, k, n) for (int i = k; i < n; i++)
#define MOD 1000000007
#define INF 1e9
#define PIE 3.14159265358979323

template <class T>
inline bool chmin(T &a, T b) {
    if (a > b) {
        a = b;
        return true;
    }
    return false;
}
template <class T>
inline bool chmax(T &a, T b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}
template <class T>
T GCD(T a, T b) {
    if (b == 0)
        return a;
    else
        return GCD(b, a % b);
}
template <class T>
inline T LCM(T a, T b) {
    return (a * b) / GCD(a, b);
}

using namespace std;
//#inculude <bits/stdc++.h>
//#define int long long

signed main() {
    int n;
    cin >> n;
    vector<pair<int, int>> m(n);
    int a, b;
    rep(i, n) {
        cin >> a >> b;
        m[i] = make_pair(a, b);
    }
    vector<vector<int>> dp(n, vector<int>(n, INF));
    rep(i, n) dp[i][i] = 0;
    for (int len = 1; len <= n; len++) {
        for (int i = 0; i < n; i++) {
            int j = i + len - 1;
            if (j >= n)
                continue;
            for (int k = i; k < j; k++) {
                chmin(dp[i][j], dp[i][k] + dp[k + 1][j] +
                                    m[i].first * m[k].second * m[j].second);
            }
        }
    }
    cout << dp[0][n - 1] << endl;
}

C++: #include<iostream>
#include<cstdio>
#include<cstdlib>
#include<string.h>

using namespace std;


int main(){

  int n;
  cin >> n;
  int m[n + 1][n + 1], p[n + 1];

  for(int i = 0; i < n; i++){
    cin >> p[i] >> p[i + 1];
    m[i][i] = 0;
  }
  m[n][n] = 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] = 1000000;
      for(int 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]);
      }
    }
  }

  cout << m[1][n] << endl;

  return 0;
}

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

using namespace std;

int main() {
	int n;
	int r[100];

	cin >> n;

	for (int i = 1; i <= n; i++) {
		cin >> r[i-1] >> r[i];
	}

	int m[100][100];

	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] + r[i - 1] * r[k] * r[j]);
			}
		}
	}
	cout << m[1][n] << endl;

	return 0;
}

C++: #include<cstdio>
#include<iostream>
#include<map>
using namespace std;
const int MAX_V = 100;
int a[MAX_V+1];
map<pair<int,int>, int> memo;

int dp(int s,int t){
  int &res=memo[make_pair(s,t)];
  if(res!=0) return res;
  if(t-s<2) return 0;
  int min=0x7fffffff;
  for(int i=s+1;i<=t-1;i++){
    int sum=dp(s,i)+dp(i,t)+a[s]*a[i]*a[t];
    if(sum<min){
      min=sum;
    }
  }
  res=min;
  return res;
}

int main(){
  int n; scanf("%d",&n);
  for(int i=0;i<n;i++){
    int fst,snd;
    scanf("%d %d",&fst,&snd);
    a[i]=fst; a[i+1]=snd;
  }
  int sum=dp(0,n);
  printf("%d\n",sum);
}

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 <string>
#include <algorithm>
using namespace std;

int main(){
	int n;
	cin >> n;
	int p[101], m[101][101];

	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<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 i = 2; i <= n; i++) {
		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][j] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
			}
		}
	}
	cout << m[1][n] << endl;

	return 0;
}