Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list {
		buf.Write([]byte(fmt.Sprintf(" %d", v)))
	}
	buf.Write([]byte("\n"))
	buf.Flush()
}

//solve
//単純な場合
func matrixChainMultiplication() {
	//行列が1つだけのとき
	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
			//kまでで区切る
			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])
			}
		}
	}
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

const MAX = 100

var n int
var p [MAX + 1]int

//m[i][j]: Mi * Mi+1 * ... * Mjを計算するときに必要なスカラー乗算の最小回数
var m [MAX + 1][MAX + 1]int

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 1; i <= n; i++ {

		p[i-1] = nextInt() //行数
		p[i] = nextInt()   //列数
	}

	matrixChainMultiplication()
	fmt.Println(m[1][n])
}

C++: #include<bits/stdc++.h>
using namespace std;
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }

const int INF = 1e8;
int main() {
	int n;
	cin >> n;
	vector<int> r(n),c(n);
	for(int i=0; i<n; i++){
		cin >> r.at(i) >> c.at(i);
	}
	
	vector<vector<int>>dp(n,vector<int>(n,INF));
	for(int i=0; i<n; i++) dp.at(i).at(i) = 0;
	for(int w=1; w<=n-1; w++){
		for(int l=0; l+w<n; l++){
			if(w==1) dp.at(l).at(l+w) = r.at(l)*c.at(l+w)*c.at(l); 
			for(int mid=l; mid<l+w; mid++){
				chmin( dp.at(l).at(l+w), dp.at(l).at(mid) + dp.at(mid+1).at(l+w) + r.at(l)*c.at(l+w)*c.at(mid));
			}
		}
	}
	cout << dp.at(0).at(n-1) << endl;
}

C++: #include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
int dp[105][105];
int p[105];
void calcu(int n)
{
  for(int i=0; i<=n; i++) dp[i][i] = 0;
  for(int num=2; num<=n; num++)// num to control the number of matrix involved in multiplication.
  {
    for(int i=1; i<=n-num+1; i++)
    {
      int j = i+num-1;
      dp[i][j] = (1 << 30);
      for(int k=i; k<j; k++)
      {
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k+1][j] + p[i-1]*p[k]*p[j]);
      }
    }

  }
  printf("%d\n", dp[1][n]);
}
int main()
{
  int n;
  scanf("%d", &n);
  for(int i=1; i<=n; i++)
  {
    scanf("%d%d", &p[i-1], &p[i]);
  }
  calcu(n);

  return 0;
}

C++: #include <iostream>
#include <vector>
#define MAX 10000001
using namespace std;

int main() {
    int num;
    cin >> num;
    int array[101][101];

    for(int i=0; i<=num; i++) {
        array[i][i] = 0;
    }

    vector<int> p;
    for(int i=0; i<num; i++) {
        int row, col;
        cin >> row >> col;
        if(i==0) p.push_back(row);
        p.push_back(col);
    }

    for(int l=0; l<num; l++) {
        for(int i=0; (i+l+1)<num; i++) {
            int j=i+l+1;
            array[i][j] = MAX;
            for(int k=i+l; k>=i; k--) {
                int value = array[i][k]+array[k+1][i+l+1]+(p[i]*p[k+1]*p[i+l+2]);
                array[i][j] = min(array[i][j],value);
            }
        }
    }
    cout << array[0][num-1] << endl;
}

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

int main()
{
	int i,j,k,l,m[101][101],p[101],n;
	
	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=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]);
			}
		}
	}
	cout << m[1][n] << endl;
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cassert>
#include <string>
#include <cstring>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>

using namespace std;

// ---------------------
// repetition
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)

// debug
#define dump(x)  cerr << #x << " = " << (x) << endl;
#define debug(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ")" << " " << __FILE__ << endl;

// ---------------------
#define INF 922337203685477580
typedef long long ll;

ll dp[110][110];
ll matrix[110][2];

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

  REP(i, N) {
    cin >> matrix[i][0] >> matrix[i][1];
  }

  for (int i = 0; i < N - 1; i++) {
    dp[i][i + 1] = matrix[i][0] * matrix[i][1] * matrix[i + 1][1];
  }
  for (int i = 0; i < N; i++) {
    dp[i][i] = 0;
  }

  // cout << dp[0][1] << endl;

  for (int l = 2; l <= N; l++) {
    for (int i = 0; i < N - l + 1; i++) {
      int j = i + l - 1;

      dp[i][j] = INF;

      for (int k = i; k < j; k++) {
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] + matrix[k][0] * matrix[k][1] * matrix[k + 1][1]);
      }
    }
  }




  cout << dp[0][N - 1] << 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=0; i<=n; i++) m[i][i] = 0;
    for (int l=2; l<=n; l++) {
        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 <cstdio>
#include <cstdlib>
#include <stack>
#include <vector>
#include <algorithm>
#include <cmath>
#include <climits>
#include <cstring>
#include <queue>
#include <string>

using namespace std;

const double PI = 3.14159265358979;


int matrix_chain_multi(int p[], int len) {	// 1 2 3 num

	int m[101][101]{};
	const int num = len - 1;
	for (int L = 2; L <= num; L++) {
		
		for (int i = 1; i <= num - L + 1; i++) {
			int j = i + L - 1;
			int minx = INT_MAX;
			for (int k = i; k < j; k++)	{
				minx = min(minx, m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
			}
			m[i][j] = minx;
		}
	}

	return m[1][len - 1];
}

int main() {

	int n; cin >> n;
	n = n + 1;

	int* p = new int[n];		// p[i-1] hang		p[i] lie
	int hang, lie, temp;
	cin >> p[0];
	for (int i = 1; i < n; i++) {
		cin >> p[i];
		if (i != n - 1)
			cin >> temp;
	}
	cout << matrix_chain_multi(p, n) << endl;


	return 0;
}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <deque>
#include <queue>
#include <list>
#include <stack>
#include <string>
#include <tuple>
#include <functional>
#include <numeric>
#include <cmath>
#include <iomanip>
#include <map>
#include <random>
#include <cstdlib>
#define INT_MAX 2147483647
#define INT_MIN -2147483646
#define Loop(i, n) for(int i = 0; i < (int)n; i++)
#define Loop1(i, n) for(int i = 1; i <= (int)n; i++)
#define Loopr(i, n) for(int i = (int)n - 1; i >= 0; i--)
#define Loopr1(i, n) for(int i = (int)n; i >= 1; i--)
using namespace std;
typedef long long int ll;

ll memo[105][105];
int r[105], c[105];

ll func(int a, int b) {
	if (b - a == 0) { 
		memo[a][b] = 0;
	}
	else {
		ll m = INT_MAX;
		for (int k = a;k < b;k++) {
			m = min(m, func(a, k) + func(k + 1, b) + r[a] * c[k] * c[b]);
		}
		memo[a][b] = m;
	}
	return memo[a][b];
}

int main() {
	int n;
	cin >> n;
	Loop(i, n) {
		cin >> r[i] >> c[i];
	}
	cout << func(0, n - 1) << endl;
	return 0;
}