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;

//using Graph = vector<vector<edge>>;
using dou =long double;
string yes="yes";
string Yes="Yes";
string YES="YES";
string no="no";
string No="No";
string NO="NO";

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(int i = 0; i < (int)(n); i++)
#define brep(n)           for(int bit=0;bit<(1<<n);bit++)
#define erep(i,container) for (auto i : container)
#define irep(i, n)        for(int i = n-1; i >= (int)0; i--)
#define rrep(i,m,n) for(ll i = m; i < (ll)(n); i++)
#define reprep(i,j,h,w) rep(i,h)rep(j,w)
#define all(x) (x).begin(),(x).end()
#define VEC(type,name,n) std::vector<type> name(n);rep(i,n)std::cin >> name[i];
#define pb push_back
#define pf push_front
#define query int qq;std::cin >> qq;rep(qqq,qq)
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define itn int
#define mp make_pair
#define sum(a) accumulate(all(a),0ll)
#define keta fixed<<setprecision
#define vvector(name,typ,m,n,a)vector<vector<typ> > name(m,vector<typ> (n,a))
#define vvvector(name,t,l,m,n,a) vector<vector<vector<t> > > name(l, vector<vector<t> >(m, vector<t>(n,a)));
#define vvvvector(name,t,k,l,m,n,a) vector<vector<vector<vector<t> > > > name(k,vector<vector<vector<t> > >(l, vector<vector<t> >(m, vector<t>(n,a)) ));
#define case std::cout <<"Case #" <<qqq+1<<": "
#define res resize
#define as assign
#define ffor for(;;)
#define ppri(a,b) std::cout << a<<" "<<b << std::endl
#define pppri(a,b,c) std::cout << a<<" "<<b <<" "<< c<<std::endl
#define aall(x,n) (x).begin(),(x).begin()+(n)
#define ssum(a) accumulate(a,0ll) 

typedef long long ll;
typedef pair<int,int> P;
typedef pair<ll,ll> PL;
//typedef long long T;
const int INF = 2000000000;
const ll INF64 = 922337203685477580ll;
const ll MOD = 1000000007ll;
const dou pi=3.141592653589793;
int main(){
    int n;
    std::cin >> n;
    std::vector<int> a(n),b(n);
    rep(i,n)std::cin >> a[i]>>b[i];
    vvector(dp,int,n+1,n+1,INF);
    rep(i,n+1)dp[i][i]=0;
    rep(i,n)dp[i][i+1]=0;
    rep(i,n-1){
        dp[i][i+2]=a[i]*b[i]*b[i+1];
     //   std::cout << dp[i][i+2] << std::endl;
    }
    
    rrep(i,3,n+1){
        rep(j,n-i+1){
            //dp[j][j+i]=min(dp[j][j+i-1]+a[j]*a[j+i-1]*b[j+i-1],dp[j+1][j+i]+b[j+i-1]*a[j]*b[j]);
            rrep(ii,j+1,i+j)chmin(dp[j][j+i],dp[j][ii]+dp[ii][j+i]+a[j]*b[j+i-1]*a[ii]);
        }
    }
    std::cout << dp[0][n] << std::endl;
    
}

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

using namespace std;

int main(){
  int N; cin >> N;
  int dp[101][101];
  fill((int*)dp, (int*)dp+101*101, 1234567890);

  vector<int> r(N), c(N);
  for(int i=0;i<N;++i){
	cin >> r[i] >> c[i];
	dp[i][i+1] = 0;
  }
  
  for(int l=2;l<=N;++l){
	for(int i=0;i+l<=N;++i){
	  for(int j=i+1;j<i+l;++j){
		dp[i][i+l] = min(dp[i][j] + dp[j][i+l] + r[i]*c[i+l-1]*r[j], dp[i][i+l]);
	  }
	}
  }
  cout << dp[0][N] << endl;
  
  return 0;
}

C++: #include <iostream>
using namespace std;
#define MAX 200
#define INFTY (1<<21)

int m[MAX][MAX], n, p[MAX];

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] = INFTY;
            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=1; i<=n; i++)
        cin >> p[i-1] >> p[i];
    matrix();
    cout << m[1][n] << endl;
    return 0;
}

C++: #include<stdio.h>

static const int N = 100;

int min(int a, int b){
  return a < b ? a : b;
}

int main(){
  int N1[N+1],N2[N+1][N+1];
  int i,j,k,l,n;
 
  scanf("%d",&n);
  for(i=1;i<=n;i++){
    scanf("%d %d",&N1[i-1],&N1[i]);
  }

  for(i=1;i<=n;i++)N2[i][i] = 0;
  for(l=2;l<=n;l++){
    for(i=0;i<=n-l+1;i++){
      j = i+l-1;
      N2[i][j] = (1<<21);
      for(k = i;k <= j-1;k++){
	N2[i][j] = min(N2[i][j],N2[i][k] + N2[k+1][j] + N1[i-1]*N1[k]*N1[j]);
      }
    }
  }

  printf("%d\n",N2[1][n]);
  
  return 0;
}

C++: #include <bits/stdc++.h>

#define REP(i, s, n) for (int i = s; i < n; i++)
#define rep(i, n) REP(i, 0, n)

using namespace std;

// data
const int MAX_N = 100;
int A[MAX_N][2]; // 0-col, 1-row
enum
{
    row, col
};

// dp
int dp[MAX_N+1][MAX_N]; // k number from A_i;
const int INF = 1 << 29;

int main(){
    int n; cin >> n;
    rep(i, n){
        cin >> A[i][row] >> A[i][col];
    }

    rep(k, n+1){
        rep(i, n){
            if (k <= 1)
                dp[k][i] = 0;
            else    
                dp[k][i] = INF;
        }
    }

    rep(k, n+1){
        rep(i, n){
            rep(j, k)
                dp[k][i] = min(dp[k][i], 
                    dp[j][i] + dp[k-j][i+j] + A[i][row]*A[i+j][row]*A[i+k-1][col]);
        }
    }

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

}

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

const int N=100;

int main(){
	int n;
	long m[N+1][N+1], p[N+1];
	
	scanf(" %d", &n);
	for(int i=1; i<=n; ++i)
		scanf(" %ld %ld", &p[i-1], &p[i]);
		
	for(int i=0; i<=n; ++i) printf("p[%d]=%ld\n", i, p[i]);
		
	for(int i=1; i<=n; ++i) m[i][i]=0;
	
	for(int s=2; s<=n; ++s){ //s??????????????????
		for(int i=1; i+s-1<=n; ++i){ //?§????i
			int j=i+s-1; //??????j
			m[i][j]=100000000; //????????§???????????§?????????
			for(int k=i; k<=j-1; ++k){ //?????????k
				m[i][j]=min(m[i][j], m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
				//printf("go %d %d %d\n",i, j, k);
			}
		}
	}
	
	printf("%ld\n", m[1][n]);
}

C++: // Chain matrix multiplication (DP)

#include <algorithm>
#include <iostream>
#include <limits>
#include <vector>

using namespace std;
int main() {
  int n;
  cin >> n;

  int a, b;
  vector<int> A, B;
  while (cin >> a >> b) {
    A.push_back(a);
    B.push_back(b);
  }

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

  // len=0 => cost = 0, the default value
  for (int len = 1; len < n; ++len) {
    for (int i = 0; i < n - len; ++i) {
      int j = i + len;
      int best = numeric_limits<int>::max();
      for (int k = i; k < j; ++k) {
        best = min(best, cost[i][k] + cost[k + 1][j] + A[i] * B[k] * B[j]);
      }
      cost[i][j] = best;
    }
  }

  cout << cost[0][n - 1] << endl;
}