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 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[0].r, matrices[len(matrices)-1].c}, v
	}
	if len(matrices) == 0 {
		panic("must not be empty")
	} else if len(matrices) == 1 {
		return matrices[0], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < len(matrices)-1; i++ {
		formerMatrices := matrices[:i+1]
		latterMatrices := matrices[i+1:]
		matF, countF := calcMinMatrixChainMultiplication(formerMatrices, Range{0, i}, memo)
		matL, countL := calcMinMatrixChainMultiplication(latterMatrices, Range{i + 1, len(matrices) - 1}, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[0].r, matrices[len(matrices)-1].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++: //	created : 16/03/13
// 	author   : Rp7rf
#include <iostream>
#include <vector>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <set>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define rep(i,a) for(int i = 0 ; i < a ; i ++)
#define loop(i,a,b) for(int i = a ; i < b ; i ++)
#define vi vector<int>
#define mp make_pair
#define pb push_back
#define MOD 1000000007
#define INF 1e9
static const int N = 100;

int main(void){
	int n, p[N+1], m[N+1][N+1];
	cin>>n;
	rep(i,n+1){
		cin>>p[i]>>p[i+1];
	}
	
    loop(i,1,n+2)m[i][i] = 0;
 
    loop(l,2,n+1){
        loop(i,1,n-l+2){
            int j = i + l - 1;
            m[i][j] = (1<<21);
            loop(k,i,j){
                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 <bits/stdc++.h>
#ifdef _DEBUG
#include "debug.hpp"
#else
#define debug(...)
#endif
#define REP(i, m, n) for(int (i) = (m); (i) < (n); ++i)
#define rep(i, n) REP(i, 0, n)
using namespace std;
typedef long long ll;
typedef pair<ll, ll> P;
const int INF = 1e9 + 7;
const ll LINF = 1LL << 60;
template<class T, class U> inline bool chmax(T &a, const U &b) { if(a < b) { a = b; return true; } return false; }
template<class T, class U> inline bool chmin(T &a, const U &b) { if(a > b) { a = b; return true; } return false; }

ll dp[110][110];

int main() {
  cin.tie(0); ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<int> rw(n), cl(n);
  rep(i,n) cin >> rw[i] >> cl[i];
  rep(i,110) rep(j,110) dp[i][j] = LINF;
  rep(i,110) dp[i][i] = 0;
  REP(i,1,n+1) rep(l,n) {
    int r = l+i;
    if(r >= n) continue;
    REP(j,l,r) {
      chmin(dp[l][r], dp[l][j]+dp[j+1][r]+rw[l]*cl[j]*cl[r]);
    }
  }
  cout << dp[0][n-1] << '\n';
  return 0;
}

C++: #include "stdafx.h"
#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++: //全くわからんので解き方を見てみる
//行列dpを作って、dp[i][j]はi~jのかけ算をした際の最小の回数
//これを順に計算すれば確かに最小のものは出そう

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

using namespace std;

int main(){
  int INF=1000000000;
  int n;cin >> n;
  vector< vector<int> > dp(n,vector<int>(n,INF));
  //vector< vector< pair<int,int> > > x(n,vector< pair<int,int> >(n,make_pair(0,0)));
  vector< pair<int,int> > m(n);
  for(int i=0;i<n;i++){
    int r,c;cin >> r >> c;
    m[i]=make_pair(r,c);
  }

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

  for(int l=0;l<n;l++){//長さのループ
    for(int i=0;i<n-l;i++){//行のループ
      if(l==0){dp[i][i+l]=0;}
      for(int j=i;j<i+l;j++){//更新のループ(d[i][i+l])
        dp[i][i+l]=min({dp[i][i+l],dp[i][j]+dp[j+1][i+l]+m[i].first*m[j].second*m[i+l].second});
      }
    }

  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
      cout << dp[i][j] << " ";
    }
    cout << endl;
  }
  */
  cout<< dp[0][n-1] << endl;

}

C++: #include <bits/stdc++.h>
typedef long long ll;
using namespace std;
ll MOD = 1000000007;

#define vec                vector<int>
#define vecll              vector<ll>
#define vecd               vector<double>
#define vecst              vector<string>
#define vecb               vector<bool>
#define vec2(var, n, m)    vector<vector<int>>  var(n, vector<int>(m, 0))
#define vecb2(var, n, m)   vector<vector<bool>> var(n, vector<bool>(m, false))
#define vecll2(var, n, m)  vector<vector<ll>>   var(n, vector<ll>(m, INF))

#define rep(i,n)         for(ll i=(ll)0; i<(ll)n; i++)
#define REP(i,m,n)       for(ll i=(ll)m; i<(ll)n; i++)
#define arr(var, n)      vec var(n); rep(i,n){cin >> var[i];}
#define arrll(var, n)    vecll var(n); rep(i,n){cin >> var[i];}
#define arrst(var, n)    vecst var(n); rep(i,n){cin >> var[i];}
#define all(var)         (var).begin(), (var).end()
#define sortall(var)     sort(all(var))
#define uniqueall(v)     v.erase(unique(v.begin(), v.end()), v.end());
#define f_sum(var)       accumulate(all(var), 0)
#define f_sumll(var)     accumulate(all(var), 0LL)
#define chmin(v1, v2)    v1 = min(v1, v2)
#define chmax(v1, v2)    v1 = max(v1, v2)
#define pb(var)          push_back(var)
#define prt(var)         cout << (var) << "\n"
#define prtd(n, var)     cout << fixed << setprecision(n) << (var) << "\n"
#define prtfill(n, var)  cout << setw(n) << setfill('0') << (var);
#define prt2(v1, v2)     cout << (v1) << " " << (v2) << "\n"
#define prt3(v1, v2, v3) cout << (v1) << " " << (v2) << " " << (v3) << "\n"
#define prtall(v)        rep(i,v.size()){cout<<v[i]<<(i!=v.size()-1?" ":"\n");}
void prtok(bool ok){prt(ok ? "YES" : "NO");}
//----------------------------------------------------------------

int main(void) {
  int n;
  cin >> n;
  vecll r(n), c(n);
  rep(i,n){
    cin >> r[i] >> c[i];
  }

  ll INF = 1e18;
  vecll2(dp, n, n);

  rep(i,n){
    dp[i][i]=0;
  }

  REP(num,2,n+1){
    rep(i,n-num+1){
      REP(k,i,i+num-1){
        ll tmp = dp[i][k] + dp[k+1][i+num-1] + r[i]*c[k]*c[i+num-1];
        chmin(dp[i][i+num-1], tmp);
      }
    }
  }

  prt(dp[0][n-1]);
}

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

int N ;
int a[101][101];
int m[101][2];

int main() {
    cin >> N;
    for (int i = 1; i <= N; ++i) {
        cin >> m[i][0] >> m[i][1];
    }

    for (int j = 1; j <= N; ++j) {
        a[j][j] = 0;
    }

    for (int k = 1; k < N; ++k) {
        for (int l = 1; l <= N- k ; ++l) {
            int j = l + k;
            int mn = INT_MAX;
            for (int p = l; p <= j-1 ; ++p) {
                mn = min(mn, a[l][p] + a[p+1][j] + m[l][0] * m[p][1] * m[j][1]);
            }
            a[l][j] = mn;
        }
    }
    cout << a[1][N] << endl;

    return 0;
}