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<stdio.h>
#include<stdlib.h>
#include<limits.h>
#define N 101

int main(){
  int a[N],b[N][N];
  int i,n,k,j,l=0,tmp=0;

  scanf("%d",&n);

  for(i=1;i<=n;i++){
    scanf("%d%d",&a[i-1],&a[i]);
  }

  for(i=1;i<=n;i++){
    b[i][i]=0;
  }
  for(j=2;j<=n;j++){
    for(i=1;i<=n-j+1;i++){
      k=i+j-1;
      b[i][k]=INT_MAX;
      for(l=i;l<=k-1;l++){
        tmp=b[i][l]+b[l+1][k]+a[i-1]*a[l]*a[k];

    if(b[i][k]>tmp){
      b[i][k]=tmp;
    }else{
      b[i][k]=b[i][k];
    }
      }
    }
  }
  printf("%d\n",b[1][n]);
  return 0;
}

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

#define MAX (1 << 21)
const int N = 1000;

int main() {
    int n;
    int m[N + 1][N + 1];
    int p[N + 1];
    for (int i = 1; i <= N; i++)
        m[i][i] = 0;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> p[i] >> p[i + 1];
    }
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= n - i + 1; j++) {
            int k = j + i - 1;
            m[j][k] = MAX;
            for (int l = j; l < k; l++) {
                m[j][k] = min(m[j][k], m[j][l] + m[l + 1][k] + p[j - 1] * p[l] * p[k]);
            }
        }
    }
    cout << m[1][n] << endl;
    return 0;
}

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

signed main(){
    // cout << fixed << setprecision(10) << flush;

    int n;
    cin >> n;
    vector<int> r(n), c(n);
    for(int i=0; i<n; i++){
        cin >> r[i] >> c[i];
    }

    // 最後の行列をどうやって掛けるか
    // (i-1)個 * 1個, (i-2) * (1 * 1), (i-3) * (2 * 1), ..., 1 * ((i-2) * 1)
    // のうちから最小を求め、ストックする
    // 0 <= i <= n
    // つまり、左から i 番目から j 番目までかけたときの最小の乗算の数、をストックしておく必要がある
    // dp[i][i] = 0
    // dp[i][j] = min_{i<=i_j<j} ((i ~ i_j までまとめたときの最小値) + r[i]*c[i_j]*c[j] + (i_j+1 ~ j-1 までまとめたときの最小値 + r[i_j+1]*c[j-1]*r[j]))
    // dp[i][j] = min_{i<=i_j<j} (dp[i][i_j] + r[i]*r[i_j]*c[j] + (dp[i_j+1][j-1] + r[i_j]*r[j]*c[j]))
    int INF = 1<<30;
    INF = INF<<30;
    vector<vector<int>> dp(n, vector<int>(n, INF));
    for(int i=0; i<n; i++){
        for(int j=0; j<=i; j++){
            dp[i][j] = 0;
        }
    }
    for(int i=n-1; i>=0; i--){
        for(int j=i+1; j<n; j++){
            dp[i][j] = dp[i][j-1] + r[i]*r[j]*c[j];
            for(int i_j=i; i_j<j; i_j++){
                dp[i][j] = min(dp[i][j], dp[i][i_j] + r[i]*r[i_j+1]*c[j] + (dp[i_j+1][j-1] + r[i_j+1]*r[j]*c[j]));
            }
        }
    }
    cout << dp[0][n-1] << endl;
    return 0;
}

C++: #include <iostream>
#include <vector>

int main(){
	int n;
	std::vector< int > r, c;
	std::vector< std::vector< int > > dp;
	
	std::cin >> n;
	r.resize(n);
	c.resize(n);
	dp.resize(n);
	
	for(int i=0; i<n; ++i){
		std::cin  >> r[i] >> c[i];
		dp[i].resize(n);
		dp[i][i] = 0;
	}
	
	for(int m=1; m<n; ++m){
		for(int i=0; i<n; ++i){
			int j = m + i;
			if(j>=n)break;
			
			int min = -1;
			for(int k=i; k<j; ++k){
				int t = dp[i][k] + dp[k+1][j] + r[i] * c[k] * c[j];
				
				if(min == -1 || min > t){
					min = t;
				}
			}
			dp[i][j] = min;
		}
	}
	
	std::cout << dp[0][n-1] << std::endl;
	
	return 0;
}

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

int main() 
{
    int n, p[210], m[110][110];
    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) 
    {
        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 <vector>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <algorithm>	// require sort next_permutation count __gcd reverse etc.
#include <cstdlib>	// require abs exit atof atoi 
#include <cstdio>		// require scanf printf
#include <functional>
#include <numeric>	// require accumulate
#include <cmath>		// require fabs
#include <climits>
#include <limits>
#include <cfloat>
#include <iomanip>	// require setw
#include <sstream>	// require stringstream 
#include <cstring>	// require memset
#include <cctype>		// require tolower, toupper
#include <fstream>	// require freopen
#include <ctime>		// require srand
#define rep(i,n) for(int i=0;i<(n);i++)
#define ALL(A) A.begin(), A.end()
#define INF 1<<25

using namespace std;

typedef long long ll;
typedef pair<int, int> P;

int a[105];
int dp[105][105];

int main()
{
	memset (a, 0, sizeof (a ) );
	memset (dp, 0, sizeof (dp ) );

	ios_base::sync_with_stdio(0);
	int n; cin >> n;

	rep (i, n+1 ) for (int j = i+1; j < n+1; j++ ) dp[i][j] = INF;

	
	rep (i, n ){
		int r, c; cin >> r >> c;
		a[i] = r; a[i+1] = c;
	} // end rep

	for (int i = n; i >= 1; i-- ){
		for (int j = i; j <= n; j++ ){
			for (int k = i; k < j; k++ ){
				int curr = dp[i][k] + dp[k+1][j];
				dp[i][j] = min (dp[i][j], curr + a[i-1]*a[k]*a[j] );
			} // end for
		} // end for
	} // end for

	int res = dp[1][n];
	cout << res << endl;

	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i=0; i < (n);++i)
using namespace std;
template <class _t> inline bool chmax (_t& a,_t b){if(a<b){a=b;return true;}return false;} template <class _t> inline bool chmin (_t& a,_t b){if(a>b){a=b;return true;}return false;}

const long long inf = 1ll << 60;
const long long mod = 1000000007;

int dx[4] = {1,0,-1,0};int dy[4] = {0,-1,0,1};

int main() {
    int n;cin >> n;
    vector<int> p(n+1,0);
    for(int i=0;i<n;i++){
	cin >> p[i] >> p[i+1];
	//p[0] M1の行 p[1] M１の列
    }
    vector<vector<int> > dp(n+1,vector<int>(n+1,(1<<21)));
    rep(i,n+1) dp[i][i] = 0;
    for(int t = 2;t<=n;t++){
	for(int i=1;i<=n-t+1;i++){
	    int j=i+t-1;
	    for(int k=i;k<=j-1;k++){
		chmin(dp[i][j],dp[i][k]+dp[k+1][j]+p[i-1]*p[k]*p[j]);
	    }
	}
    }
    /*
    for(int i=0;i<=n;i++){
	for(int j=0;j<=n;j++){
	    cout << dp[i][j] << " ";
	}
	cout << endl;
    }
    */
    cout << dp[1][n] << endl;
    return 0;
}