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>
#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[i][j] << endl;
			}
		}
	}

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

	return 0;
}

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

static const int N=100;

int main()
{
    int n;
    int 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>

#define rep(i,n) for(int i = 0; i < (n); i++)
#define rrep(i,n) for(int i = (n)-1; i >= 0; i--)
#define rep1(i,n) for(int i = 1; i <= (n); i++)
#define rrep1(i,n) for(int i = (n); i > 0; i--)

#define ll long long
#define pi pair<int, int>
#define pll pair<ll, ll>

#define MOD 1000000007
#define INF 1000000000

using namespace std;

#define MAXN 101
int dp[MAXN][MAXN];

int main(){
  int n;cin>>n;
  vector<int> r(n),c(n), rc(n+1);
  rep(i, n){
    cin>>r[i]>>c[i];
    rc[i]=r[i];
  }
  rc[n]=c[n-1];
  n++;

  // rep(i, n)cout<<rc[i]<<' ';cout<<endl;
  // rep(i, n-1)cout<<r[i]<<' ';cout<<endl;
  // rep(i, n-1)cout<<c[i]<<' ';cout<<endl<<endl;

  // 行列数2について予め計算しておく
  rep(i, n-2)dp[i][i+2]=rc[i]*rc[i+1]*rc[i+2];

  // rep(i, n){rep(j, n)cout<<dp[i][j]<<' ';cout<<endl;}
  // cout<<endl;

  // 計算対象となる行列の数
  for(int len=3; len<=n; len++){
    // 行列の個数が入る分だけ左端から全て計算する
    rep(i, n-len+1){
      int j=i+len;
      dp[i][j]=INF;
      // lenの中で最後に計算する場所についてループを回して全チェック
      // 両端を含む必要はないのでkはi+1で初期化し、i+len-1までのループにする。
      for(int k=i+1; k<j; k++){
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k][j] + rc[i]*rc[j]*rc[k]);
        // cout<<i<<' '<<k<<' '<<j<<'|'<<dp[i][k]<<' '<<dp[k][j]<<' '<<rc[i]*rc[j]*rc[k]<<endl;
      }

      // rep(i, n){rep(j, n)cout<<dp[i][j]<<' ';cout<<endl;}cout<<endl;

      // cout<<endl;
    }
  }

  cout<<dp[0][n-1]<<endl;

  // rep(i, n){rep(j, n)cout<<dp[i][j]<<' ';cout<<endl;}
  // cout<<endl;

  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,a,b) for(int i=int(a);i<int(b);++i)
#define SIZE 200005
#define INF 1000000005LL
//#define INF 1e18
#define MOD 1000000007

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

int n;
ll p[105];
ll dp[105][105];

int main(){

  cin >> n;
  rep(i,0,n){
    cin >> p[i] >> p[i+1];
  }

  fill(dp[0],dp[105],INF);
  rep(i,0,104){
    dp[i][i+1] = 0;
  }

  rep(k,2,n+1) rep(i,1,n+1){
    int j = i+k;
    if(j>=n+2)continue;
    rep(l,i,j-1) {
      dp[i][j] = min(dp[i][j],dp[i][l+1] + dp[l+1][j] + p[i-1]*p[l]*p[j-1]);
      //cout << i<<j<<k<<l << " " << dp[i][j] << endl;
    }
  }

  cout << dp[1][n+1] << endl;

  return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <utility>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <cmath>
#include <queue>
using namespace std;
typedef long long ll;
const int INF = 1<<30; 
const int MOD = 1e9 + 7;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    int rc[110];
    for(int i = 1; i <= n; i++) cin >> rc[i - 1] >> rc[i];
    int dp[110][110];
    for(int i = 0; i < 110; i++) for(int j = 0; j < 110; j++) dp[i][j] = INF;
    for(int i = 1; i <= n; i++) dp[i][i] = 0;
    for(int alpha = 2; alpha <= n; alpha++)
    {
        for(int l = 1; l <= n - alpha + 1; l++)
        {
            int r = l + alpha - 1;
            for(int k = l; k <= r; k++)
            {
                dp[l][r] = min(dp[l][r], dp[l][k] + dp[k + 1][r] + rc[l - 1] * rc[k] * rc[r]);
            }
        }
    }
    cout << dp[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 <climits>
#define MAX 101
#define INF LLONG_MAX
using namespace std;

//the minimum matrix chain multiplication of M_i...M_j
long long m[MAX][MAX];
//M_i is p[i-1]*p[i]
long long p[MAX];

int main(){
  int n; cin >> n;
  cin >> p[0];
  for(int i=1;i<=n-1;i++){
    cin >> p[i];
    int x; cin >> x;
  }
  cin >> p[n];
  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]=INF;
      //find the minimum of M_i...M_j
      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<climits>
using namespace std;
int m[100][100];

int MCM(int p[],int n) {
	for (int i = 0; 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] = INT_MAX;
			for (int k = i; k <= j; k++) {
				int q = m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j];
				if (m[i][j] > q) {
					m[i][j] = q;
				}

			}
		}

	}
	return m[1][n];
}

int main() {
	int n, p[200];
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> p[i] >> p[i + 1];
	}
	cout << MCM(p, n) << endl;
	return 0;
}