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 <iostream>
using namespace std;
int n, a[111], b[111], dp[111][111];
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) cin >> a[i] >> b[i];
	for(int i = 2; i <= n; i++) {
		for(int j = 0; j <= n - i; j++) {
			int l = j, r = j + i; // [l, r)
			dp[l][r] = 999999999;
			for(int k = l + 1; k < r; k++) {
				dp[l][r] = min(dp[l][r], dp[l][k] + dp[k][r] + a[l] * a[k] * b[r - 1]);
			}
		}
	}
	cout << dp[0][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 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<stdio.h>
#define  N 100
 
int main() {
  int n,p[N+1], m[N+1][N+1];
  scanf("%d",&n);
  for (int i = 1;i <=n; i++) {
    scanf("%d %d",&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; i++){
    int j = i + l -1;
    m[i][j] = 10000000;
    for (int k = i;k <= j -1;k++) {
      if(m[i][j]>m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j])
      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>

using namespace std;
const int dx[]={1,0,-1,0,1,-1,-1,1,0};
const int dy[]={0,1,0,-1,1,1,-1,-1,0};
const int INF = 1e9+101;
const long long LINF = 1e18;
const double EPS = 1e-8;
#define pb push_back
#define mk make_pair
#define fr first
#define sc second
#define reps(i,j,k) for(int i = (j); i < (k); ++i)
#define rep(i,j) reps(i,0,j)
#define all(a) (a).begin(),(a).end()
#define MOD 1000000007
typedef long long ll;
typedef pair<int,int> Pii;
typedef pair<ll, ll> Pll;
typedef pair<Pii,int> P;
typedef vector<int> vi;
typedef vector<ll> vll;
template<class T>
ostream& operator<<(ostream &out, const vector<T> &v){
	out << "{";
	rep(i,v.size()){
		out << v[i] <<", ";
	}
	return out << "}" << endl;
}
Pll rc[128];
ll memo[128][128];
// [left, right)
ll solve(int left, int right) {
    if(memo[left][right] != -1) return memo[left][right];
    if (right - left <= 1) {
        return memo[left][right] = 0;
    }
    ll mn = LINF;
    reps(i, left+1, right) {
        ll cost = rc[left].first*rc[i-1].second*rc[right-1].second;
        mn = min(mn, solve(left, i) + solve(i, right) + cost);
    }
    return memo[left][right] = mn;
}
int main() {
    memset(memo,-1,sizeof(memo));
    int N;
    cin >> N;
    rep(i,N){
        int r,c;
        cin >> r >> c;
        rc[i] = mk(r,c);
    }
    cout << solve(0, N) << endl;
    return 0;  
}

C++: #include <bits.stdc++.h>
#define MAX 100
using namespace std;

int M[MAX][MAX];
int P[MAX][MAX];
int main(){
  int n;
  cin >> n;
  for(i = 1; i <= n; i++){
    cin >> P[i-1] >> P[i];
  }
  Ans = matrixChainMultiplication();
  return 0;
}


int matrixChainMultiplication(){
  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] = INFINITY;
  }
  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]);
  }
  return M[i][j];
}

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

struct Mat{
	  int r,l;
};

int main(){

	  int n; cin >> n;
	  vector<Mat> Mats(n);
	  for(int i=0; i<n; i++)
			cin >> Mats[i].r >> Mats[i].l;

	  int dp[n][n] = {};
	  for(int i=0; i<n; i++)
			for(int j=0; j<n; j++)
				  if(i==j) dp[i][j] = 0;
				  else dp[i][j] = INT_MAX;

	  for(int k=1; k<n; k++){
			for(int i=0; i+k<n; i++){
				  for(int j=i; j<i+k; j++){
						int num_prod = Mats[i].r * Mats[j+1].r * Mats[i+k].l;
						dp[i][i+k] = min(dp[i][i+k], dp[i][j] + dp[j+1][i+k] + num_prod);
				  }
			}
	  }
	  
	  cout << dp[0][n-1] << endl;
	  
			
}

C++: #include <stdio.h>
#include <algorithm>

using namespace std;


int main(){
	int n,minimum,tmp;
	scanf("%d",&n);
	int table[n][n];
	int data[n][2];

	for(int i=0;i<n;i++){
		for(int k=0;k<n;k++)table[i][k] = 0;
		scanf("%d %d",&data[i][0],&data[i][1]);
	}

	for(int i=n-2;i>=0;i--){
		for(int k=0;k<=i;k++){
			if(i==n-2){
				table[n-i-1][k] = data[k][0]*data[k][1]*data[k+1][1];
		}else{
				minimum = 2147483647;
				for(int p=0;p<=n-i-2;p++){
					tmp=(table[p][k]+table[n-i-p-2][k+p+1])+(data[k][0]*data[k+p][1]*data[k+n-i-1][1]);
					minimum = min(minimum,tmp);
				}
				table[n-i-1][k] = minimum;
			}
		}
	}

	printf("%d\n",table[n-1][0]);

    return 0;
}

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

int matrixChainOrder(vector<int> &p){
  auto n = p.size() - 1;
  int mat[n + 1][n + 1];
  for(auto i = 1; i <= n; i++){
    mat[i][i] = 0;
  }

  for(auto l = 2; l <= n; l++){
    for(auto i = 1; i <= n - l + 1; i++){
      auto j = i + l - 1;
      mat[i][j] = 1000000;

      for(auto k = i; k <= j - 1; k++){
        auto q = mat[i][k] + mat[k + 1][j] + p[i - 1] * p[k] * p[j];
        if(q < mat[i][j]){
          mat[i][j] = q;
        }
      }

    }
  }


  return mat[1][n];
}

int main(){
  int n;
  cin >> n;

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

  cout << matrixChainOrder(mat) << endl;

  return 0;
}