Go: package main

/*
連鎖行列積
*/

import (
	"bufio"
	"bytes"
	"fmt"
	"log"
	"math"
	"os"
	"strconv"
	"strings"
)

func min(a, b int) int {
	if a < b {
		return a
	}
	return b
}

type mem *[][]int

func main() {
	scanner := makeScanner(1024)
	n := eGetInt(scanner)
	p := make([]int, n+1)
	for i := 0; i < n; i++ {
		rowcol := eGetInts(scanner)
		p[i] = rowcol[0]
		p[i+1] = rowcol[1]
	}
	m := make([][]int, n)
	for i := 0; i < n; i++ {
		m[i] = make([]int, n)
	}
	// 初期値の格納
	for i := 0; i < n; i++ {
		for j := i; j < n; j++ {
			if i == j {
				m[i][j] = 0 //  同じ行列へのコストは当然0
			} else {
				m[i][j] = math.MaxInt64
			}
		}
	}

	// num : 行列の数. num == 1の場合は初期値0を格納ずみ
	for num := 2; num <= n; num++ {
		// s : スタート行列番号
		for s := 0; s+num <= n; s++ {
			// t : 終了行列番号
			t := s + num - 1
			// k : 仕切
			for k := s; k < t; k++ {
				m[s][t] = min(m[s][t], m[s][k]+m[k+1][t]+p[s]*p[k+1]*p[t+1])
			}
		}
	}
	fmt.Println(m[0][n-1])
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

type ints []int

func (s ints) String() string {
	var buf bytes.Buffer
	buf.WriteString("[")
	sep := ""
	for _, v := range s {
		buf.WriteString(fmt.Sprintf("%s%d", sep, v))
		sep = ", "
	}
	buf.WriteString("]")
	return buf.String()
}

func reverse(a ints) ints {
	r := make(ints, len(a))
	for i := 0; i < len(a); i++ {
		r[i] = a[len(a)-1-i]
	}
	return r
}
func max(a ints) (int, bool) {
	if len(a) == 0 {
		return 0, false
	}
	m := a[0]
	for _, e := range a {
		if e > m {
			m = e
		}
	}
	return m, true
}

// func min(a []int) int {
// 	m := a[0]
// 	for _, v := range a {
// 		if v < m {
// 			m = v
// 		}
// 	}
// 	return m
// }

func sum(a ints) int {
	if len(a) == 0 {
		return 0
	}
	sum := 0
	for _, e := range a {
		sum += e
	}
	return sum
}
func find(n int, a ints) int {
	for i, v := range a {
		if n == v {
			return i
		}
	}
	return -1
}

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

int CountMulti(const int& r1,const int& c1,const int& r2,const int& c2){
	return c1*c2*r1;
}

int main(void){
	int N;
	cin >> N;
	vector<long long> rows(N),cols(N);
	for(int i=0;i<N;i++)
		cin >> rows[i] >> cols[i];

	const long long INF = 1e18;
	long long dp[101][101];
	memset(dp,0,sizeof(dp));
	for(int i=0;i<N;i++){
		for(int j=0;j<N;j++){
			if(i == j)dp[i][j] = 0;
			else dp[i][j] = INF;
		}
	}
	for(int i=0;i<N-1;i++){
		dp[i][i+1] = rows[i]*rows[i+1]*cols[i+1];
	}

	for(int d=2;d<N;d++){
		for(int l=0;l<N-d;l++){
			for(int r=l;r<l+d;r++){
				dp[l][l+d] = min(dp[l][l+d], dp[l][r] + dp[r+1][l+d] + rows[l]*rows[r+1]*cols[l+d]);
			}
		}
	}
	cout << dp[0][N-1] << endl;
	return 0;
}

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

using P = pair<int, int>;

int nmul(int x, int y, int z){
    return x*y*z;
}

int main(){
    int n; cin >> n;
    vector<int> M(n+1);
    int dummy;
    for(int i=0; i<n; ++i){
        cin >> M[i] >> dummy;
    }
    M[n] = dummy;
    vector<vector<int>> dp(n+1, vector<int>(n+1, numeric_limits<int>::max()));
    // dp[i][i+l] = M_i から M_{i+l} までの行列乗算の最適コスト
    for(int l=0; l<n; ++l) dp[l][l] = 0;

    for(int L=1; L<n; ++L){
        for(int l=0; l<n-L; ++l){
            for(int k=0; k<L; ++k){
                dp[l][l+L] = min(dp[l][l+L], dp[l][l+k] + dp[l+k+1][l+L] + nmul(M[l],M[l+k+1],M[l+L+1]));
            }
        }
    }
    cout << dp[0][n-1] << endl;
}

C++: #include<iostream>
#include<cmath>
#include<algorithm>
#include<string>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<iomanip>
#include<bitset>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> P;
typedef pair<ll,P> P1;
typedef pair<P,P> P2;
#define pu push
#define pb push_back
#define mp make_pair
#define eps 1e-7
#define INF 1000000000
#define fi first
#define sc second
#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)
#define SORT(x) sort(x.begin(),x.end())
#define ERASE(x) x.erase(unique(x.begin(),x.end()),x.end())
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin())
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin())

const int MAX = 510000;
const int MOD = 1000000007;

ll dp[210][210];
// dp[i][j] は from i to jまで　の積の計算の最小回数

int main(){
  ll N; cin >> N;
  vector<P> a(N); rep(i,N) cin >> a[i].fi >> a[i].sc;

  // dp 初期化
  rep(i,N) rep(j,N) dp[i][j] = INF;
  rep(i,N) dp[i][i] = 0;

  repn(i,N){
    // iはいくつ離れてるか
    rep(j,N){
      // j is start
      for(ll k = j; k <= i + j; k++){
        // k が空いてた
        if(k == j){
          dp[j][j + i] = min(dp[j][j + i] , a[k].fi * a[k].sc * a[j + i].sc  + dp[j + 1][j + i]);
        }
        else if(k == i + j){
          dp[j][j + i] = min(dp[j][j + i] , dp[j][j + i - 1] + a[j].fi * a[k].fi * a[k].sc);
        }
        else{
          dp[j][j + i] = min(dp[j][j + i] ,
            dp[j][k] + a[j].fi * a[k].sc * a[j + i].sc + dp[k + 1][j + i]);
        }
      }
    }
  }

  // rep(i,N) rep(j,N) cout << i << " " << j << " " << dp[i][j] << endl;

  cout << dp[0][N - 1] << endl;
}

C++: #include <iostream>
#include <cstdio>
#include <map>
#define MAX_NUM 100
#define INFTY 1000000000

using namespace std;

//think easy make easy

int n;//num of input


pair<int,int> MatrixChain[MAX_NUM+1];

int calc(int s,int e){//s~eの連鎖行列積の最少計算回数を出力
	int min_time  = INFTY;

	int min_tmp;
	if(s == e){
		return 0;
	}
	for(int i=s;i<e;i++){
		min_tmp = calc(s,i) + calc(i+1,e) 
			+MatrixChain[s].first*MatrixChain[i].second*MatrixChain[e].second;
		if(min_tmp < min_time)
			min_time = min_tmp;
	}
	return min_time;
}

int main(){
	scanf("%d",&n);
	int r,c;//row,column

	for(int i=0;i<n;i++){
		scanf("%d %d",&r,&c);
		MatrixChain[i] = pair<int,int>(r,c);//i:1~n-1
	}

	cout <<calc(0,n-1) <<endl;

	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MOD=1000000007;
#define INF 1LL<<30
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()

int main() {
    int n;
    cin>>n;
    int m[n+1][n+1],p[n+1];
    rep(i,n){
        cin>>p[i]>>p[i+1];
        m[i][i]=0;
    }
    m[n][n]=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;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;
}