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;

#define N 100
#define INF 1000000
int main(){
	int n, tmp, p[N + 1], dp[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++){
		dp[i][i] = 0;
	}
	
	for(int l = 2 ; l <= n ; l++){    //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++){
				tmp = dp[i][k] + dp[k + 1][j] + p[i - 1] * p[k] * p[j];
			if(dp[i][j] > tmp) dp[i][j] = tmp;
			else dp[i][j] = dp[i][j];
				}
		}
	}
	
	cout << dp[1][n] << endl;
	
	return 0;
}

C++: #include<cstdio>
#include<algorithm>
static const int 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+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]);
      }
    }
  }
  printf("%d\n",m[1][n]);
  return 0;
}

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

int n;

int m[101][101];

int p[101];


void matrix(){
  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] = 1000000;
      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]);
      }
    }
  }
}

int main(){

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

  matrix();



  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 <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <unordered_map>
#include <vector>
#include <string.h>
#include <set>

using namespace std;

#define COUT(x) cout << #x << " = " << (x) << " (L" << __LINE__ << ")" << endl

template<class T> void printvec(const vector<T>& v) {
  for (auto x : v) { cout << x << " "; }
  cout << endl;
}
template<class T> void printtree(const vector< vector<T> >& tree) {
  for (long long i = 0; i < tree.size(); ++i) {
    cout << i + 1 << ": "; printvec(tree[i]);
  }
}
template<class T, class U> void printmap(const map<T, U>& mp) {
  for (auto x : mp) { cout << x.first << "=>" << x.second << endl; }
}

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; }

#define rep(i, n) for(ll i = 0; i < n; ++i)
#define all(s) s.begin(), s.end()
#define sz(x) (ll)(x).size()
#define fr first
#define sc second
#define mp make_pair
#define pb push_back
#define eb emplace_back

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll> P;
typedef tuple<ll, ll, ll> triple;
typedef double D;
typedef vector<ll> vl;
typedef vector<P> vp;

const ll INF = 1e9;
const ll MOD = 1000000007;  // 1e9 + 7

int main(int argc, char** argv) {
  cin.tie(NULL);
  cout.tie(NULL);
  ios_base::sync_with_stdio(false);
  //cout << setprecision(10) << fixed;

  ll n;
  cin >> n;
  vector<ll> r(n);
  vector<ll> c(n);
  rep(i, n) {
    cin >> r[i] >> c[i];
  }

  // dp[i][j] .. min of dp[i][k] + dp[k+1][j] + r[i]*c[k]*c[j]. (dp[i][j] = 0 if i == j).
  vector<vector<ll>> dp(n, vector<ll>(n, INF));
  rep(i,n) { dp[i][i] = 0; }
  rep(d,n+1) {
    rep(i,n) {
      ll j = i+d-1;
      if (j >= n) { continue; }
      for (ll k = i; k < j; ++k) {
        chmin(dp[i][j], dp[i][k] + dp[k+1][j] + r[i]*c[k]*c[j]);
      }
    }
  }
  // printtree(dp);
  cout << dp[0][n-1] << endl;
}

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;
}

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

typedef long long ll;
#define inf 1e9+7

int n;
ll dp[102][102];
ll p[102];

void init(){
    for(int i=0;i<=n;i++){
        for(int j=0;j<=n;j++){
            dp[i][j]=inf;
        }
        dp[i][i]=0;
    }
}

void cal(int l, int r){
    if(l>=r)return;
    if(dp[l][r]<inf)return;
    for(int k=l;k<r;k++){
        cal(l,k);
        cal(k+1,r);
        dp[l][r] = min(dp[l][r], dp[l][k]+dp[k+1][r]+p[l]*p[k+1]*p[r+1]);
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> n;
    init();
    cin >> p[0] >> p[1];
    ll a,b;
    for(int i=1;i<n;i++){
        cin >> a >> b;
        p[i+1]=b;
    }
    cal(0,n-1);
    cout << dp[0][n-1] << endl;
    return 0;
}