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;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(obj) (obj).begin(),(obj).end()
typedef long long ll;
ll mod=2e12;
ll cnt=0;
#define nil -1
int p[200];
int c[200][200];

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;cin>>n;
    for(int i=1;i<=n;i++) cin>>p[i-1]>>p[i];
    for(int i=0;i<=n;i++)c[i][i]=0;
    for(int l=2;l<=n;l++){
      for(int i=1;i<=n-l+1;i++){
        int j=i+l-1;
        c[i][j]=(1<<21);
        for(int k=i;k<=j-1;k++){
          c[i][j]=min(c[i][j],c[i][k]+c[k+1][j]+p[i-1]*p[k]*p[j]);
        }
      }
    }
    cout<<c[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++){//因l(字母)1(数字）分不清，本人将其改?大写字母L 
        for(int i=1;i<=n-L+1;i++){
            int j=i+L-1;
            m[i][j]=(1<<21);//本人注解，相当于INF
            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;//本人注解，注意此?是1(数字)而不是l(字母) 
    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<bits/stdc++.h>
using namespace std;

const int N=505;
int mat[N][2];
int mem[N][N];

int mcm(int l, int r){
  if(l==r)  return mem[l][r]=0;
  if(mem[l][r]!=-1) return mem[l][r];
  int ret = INT_MAX;
  for (int i = l; i < r; ++i){
    int now = mcm(l, i);
    now += mcm(i+1, r);
    now += mat[l][0]*mat[i][1]*mat[r][1];
    ret = min(ret, now);
  }
  return mem[l][r]=ret;
}

int main(){
  ios::sync_with_stdio(0);
  cin.tie(0);
  
  int n;  cin >> n;
  for (int i = 0; i < n; ++i){
    cin >> mat[i][0] >> mat[i][1];
  }
  memset(mem, -1, sizeof(mem));
  cout << mcm(0, n-1) << "\n";
  return 0;
}

C++: #include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i< (n);i++)
using namespace std;
typedef long long ll;
const int INF = (1e+9)+7;

int main(){
    int n;cin>>n;
    vector<vector<int>> C(n+1,vector<int>(n+1,0));
    //↑pの為に一つ多く作った。index番号が行列の番号と一致。
    vector<int> p(n+1);
    rep(i,n){
        int a,b;cin>>a>>b;
        if(i == 0){
            p[0] = a;
            p[1] = b;
        }else{
            p[i+1] = b;
        }
    }
    for(int l = 2;l<=n;l++){
        //lは行列の個数.
        for(int i = 1; i+l-1 <= n; i++){
            int j = i+l-1;//左端のindex
            int mn = INF;
            for(int k = i;k<j;k++){
                mn = min(mn,C[i][k]+C[k+1][j]+p[i-1]*p[k]*p[j]);
            }
            C[i][j] = mn;
        }
    }
    cout<<C[1][n]<<endl;
    return 0;
}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>



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;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;

int main(){
  int n, p[101], m[101][101], i, j, k, l;
  cin >> n;
  for(i = 1;i <=n;i++){
    cin >> p[i-1] >> p[i];
  }

  for(i = 1;i <= n;i++) m[i][i] = 0;
  for(l = 1;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]);
      }
    }
  }

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

  return 0;
}

C++: #include <algorithm>
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> P;
typedef pair<ll, ll> LLP;

const int INF = (1 << 30) - 1;
// const ll LL_INF = (1LL << 62) - 1;
// const ll MOD = 1e9 + 7;
// const double PI = M_PI;

int N;
vector<int> R, C;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> N;
  R.resize(N);
  C.resize(N);
  rep(i, N) { cin >> R[i] >> C[i]; }

  int dp[N][N + 1];
  rep(i, N) { fill(dp[i], dp[i] + N + 1, 0); }

  for (int i = 2; i <= N; i++) {
    for (int l = 0; l < N; l++) {
      int r = l + i;
      if (r > N) {
        continue;
      }
      dp[l][r] = INF;
      for (int k = l + 1; k < r; k++) {
        dp[l][r] = min(dp[l][r], dp[l][k] + dp[k][r] + R[l] * R[k] * C[r - 1]);
      }
    }
  }
  cout << dp[0][N] << endl;
  return 0;
}