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 <iostream>
#include <vector>
#include <utility>


#define inf 1000000007

using namespace std;

int main(){
	int n;
	cin >> n;
	vector<pair<int,int> > m(n);
	for(int i=0;i<n;++i)cin >> m[i].first >> m[i].second;
	vector<vector<int> > dp;
	dp.resize(n);
	for(int i=0;i<n;++i){
		dp[i].resize(n);
		for(int j=0;j<n;++j)dp[i][j] = 0;
	}
	vector<int> p;
	for(int i=0;i<n;++i)p.push_back(m[i].first);
	p.push_back(m[n-1].second);
	for(int i=1;i<n;++i){
		for(int j=0;j+i<n;++j){
			dp[j][i+j] = inf;
			int t = i+j;
			for(int k=j+1;k<=t;++k){
				dp[j][t] = min(dp[j][t],dp[j][k-1]+dp[k][t]+p[j]*p[k]*p[t+1]);
			}
		}
	}
	cout << dp[0][n-1] << endl;
}

C++: /*
　　　∫ ∫ ∫
　　　ノヽ
　　（＿　 ）
　（＿　　　 ）
（＿＿＿＿＿＿ ）
　ヽ(´･ω･)ﾉ　
　　 |　 /
　　 UU
*/
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
using P = pair<ll, ll>;
const int MOD = (int)1e9 + 7;
const ll INF = 1LL << 60;
const int inf = 1<<30;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define REP(i, n) for (int i = 0; i < (n); i++)
#define FOR(i,s,n) for (int i = s; i < (n); i++)
#define ALL(obj) (obj).begin(), (obj).end() //コンテナじゃないと使えない!!
#define debug(x) cerr << #x << ": " << x << "\n";
#define mp make_pair
template <typename T>
ostream& operator<<(ostream& os, vector<T> &V){
    int N = V.size();
    REP(i,N){
        os << V[i];
        if (i!=N-1) os << " ";
    }
    os << "\n";
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, pair<T,T> const&P){
    os << P.first;
    os << " ";
    os << P.second;
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, set<T> &S){
    auto it=S.begin();
    while(it!=S.end()){
        os << *it;
        os << " ";
        it++;
    }
    os << "\n";
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, deque<T> &q){
    for(auto it=q.begin();it<q.end();it++){
        os<<*it;
        os<<" ";
    }
     os<<endl;
    return os;
}
//fixed<<setprecision(10)<<ans<<endl;
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<int> A(N+1);
    REP(i,N){
        int a,b;
        cin >> a >> b;
        A[i]=a;
        A[i+1]=b;
    }

    int ans=0;
    vector<vector<int>> dp(N,vector<int>(N,inf));
    REP(i,N) dp[i][i]=0;

    for(int i=1;i<N;i++){
        for(int left=0;left<N-i;left++){
            int right = left+i;
            for(int k=0;k<i;k++){
                int mid = left+k;
                chmin(dp[left][right], dp[left][mid] + A[left]*A[mid+1]*A[right+1] + dp[mid+1][right] );
            }
        }
    }
    ans = dp[0][N-1];
    cout << ans << endl;
}

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

template<class T> inline void chmin(T &a, const T &b) { if(a > b) a = b; }

int mul(const int r1, const int c1, const int r2, const int c2) {
	assert(c1 == r2);
	return r1 * c2 * r2;
}

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

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

	constexpr int INF = (1 << 29);
	vector<vector<int>> dp(n, vector<int>(n + 1, INF));
	for(int i = 0; i < n; ++i) {
		dp[i][i + 1] = 0;
	}

	for(int len = 0; len <= n; ++len) {
		for(int l = 0; l + len <= n; ++l) {
			const int r = l + len;
			for(int i = l + 1; i < r; ++i) {
				chmin(dp[l][r], dp[l][i] + dp[i][r] + mul(R[l], C[i - 1], R[i], C[r - 1]));
			}
		}
	}

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

	return EXIT_SUCCESS;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define MAXN 102
#define INF 10000000
int dp[MAXN][MAXN];
int p[MAXN];
int main(){
    int n;
    scanf("%d", &n);
    scanf("%d", p);
    int x;
    for(int i = 1; i < n; i++)
        scanf("%d%d", &x, p + i);
    scanf("%d", p + n);
    for(int i = 1; i <= n; i++)
        dp[i][i] = 0;
    for(int l = 1; l < n; l++){
        for(int i = 1; i + l <= n; i++){
            int j = i + l;
            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] + p[i - 1] * p[k] * p[j]);
            }
        }
    }
    printf("%d\n", dp[1][n]);
    return 0;
}

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

using namespace std;

#define INF 1e9

int main(){
  int n;

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

  p.push_back(r[0]);
  for(int i = 0 ; i < n ; i++){
    p.push_back(c[i]);
  }

  int dp[n+1][n+1];
  for(int i = 0 ; i <= n ; i++){
    dp[i][i] = 0;
  }

  for(int l = 2 ; l <= n ; l++){
    for(int i = 1 ; i <= n-l+1 ; i++){
      int j = i + l - 1;
      dp[i][j] = INF;
      for(int k = i ; k <= j-1 ; k++){
	int cost = dp[i][k] + dp[k+1][j] + p[i-1]*p[j]*p[k];
	dp[i][j] = min(dp[i][j],cost);
      }
    }
  }

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

  return 0;
}