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 <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional>

#define mp       make_pair
#define pb       push_back
#define all(x)   (x).begin(),(x).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define repi(i,a,b) for(int i = (a); i < (b); i++)

using namespace std;

typedef    long long          ll;
typedef    unsigned long long ull;
typedef    vector<bool>       vb;
typedef    vector<int>        vi;
typedef    vector<vb>         vvb;
typedef    vector<vi>         vvi;
typedef    pair<int,int>      pii;

const int INF=1<<29;
const double EPS=1e-9;

const int dx[]={1,0,-1,0},dy[]={0,-1,0,1};
int n;//計算する行列の数
const int MAX_N =110;
int dp[MAX_N][MAX_N];//dp[i][j]:=Ai...Ajの計算に必要な最小のコスト
pii A[MAX_N];//行列firstを行secondを列とする。
int B[MAX_N+1][MAX_N+1]; //B[i][j]:=Ai...Ajに最適な括弧を挿入する場所
void init(){
	for(int i =0; i < n;i++){
		for(int j = 0;j < n;j++){
			dp[i][j]=INF;
			B[i][j]=0;
		}
	}
	for(int i =0;i < n;i++){
		dp[i][i]=0;
	}
}
//計算
int solve(){
	for(int k =1;k <n;k++){//個数
		for(int i =0;i <n-k;i++){//何処から始めるか
			for(int j =i;j <i+k;j++){//何処で終わるか
				int sz =A[i].first*A[j].second*A[i+k].second;
				int cost=dp[i][j]+dp[j+1][i+k]+sz;
				if(dp[i][i+k] >cost){
					dp[i][i+k]=cost;
					B[i][i+k]= j+1;//括弧を挿入する場所
				}

			}
		}
	}
	return dp[0][n-1];
}
//復元
void order(int i,int j){
	if(i==j){
		cout <<'A'<<i;
	}else{
		cout <<"(";
		order(i, B[i][j]-1);
		order(B[i][j], j);
		cout <<")";
	}
}

int main(){
	cin>>n;
	init();
	for(int i =0;i < n;i++){
		cin>>A[i].first>>A[i].second;
	}
	cout <<solve()<<endl;
	//order(0, n-1);
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n) ; i++)
#define rrep(i,n) for(int i = n-1; i >= 0 ; i--)
constexpr auto INF = 2147483647;
typedef long long ll;

// void DebugGrid(int row, int column, auto table){
//   cout << endl;
//   rep(i,row){
//     rep(j,column) cout << table[i][j] << " ";
//     cout << endl;
//   }
// }

int main(){

  ll ans, n, DP[100][100];
  vector<pair<int,int>> matrix;
  cin >> n;
  rep(i,n){
    pair<int,int> inp;
    cin >> inp.first >> inp.second;
    matrix.emplace_back(inp);
  }

  rep(i,n)rep(j,n) DP[i][j] = INF;
  for(int l=0; l<n; l++)for(int i=0; i<n-l; i++){
    if(l == 0) DP[i][i] = 0;
    else{
      for(int j=i;j<=i+l;j++){
      DP[i][i+l] = min(DP[i][i+l],DP[i][j]+DP[j+1][i+l] + (matrix[i].first*matrix[j].second*matrix[i+l].second));
      }
    }
  }

  // DebugGrid(n,n,DP);
  cout << DP[0][n-1] << endl;
  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <numeric>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <tuple>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define show(a, n) rep(i,n) {cout<<a[i]<<' ';} cout<<endl;

using namespace std;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<long long, long long> pll;

const int INF = 1 << 30;
const long long INFL = 1LL << 62;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100010;

struct mat {
	ll r, c;
};

int main() {
//	cout << fixed << setprecision(15);
	int n;
	cin >> n;
	vector<mat> m(n);
	rep(i, n) cin >> m[i].r >> m[i].c;

	if(n == 1) {cout << 0 << endl; return 0; }

	vector<vll> dp(n, vll(n));
	rep(i, n) dp[i][i] = 0;
	int l, r;
	for(int d = 1; d <= n - 1; d++) {
		for(l = 0; l + d < n; l++) {
			r = l + d;
			dp[l][r] = INFL;
			for(int k = l; k + 1 <= r; k++) {
				dp[l][r] = min(dp[l][k] + dp[k + 1][r] + m[l].r * m[k].c * m[r].c, dp[l][r]);
			}
		}
	}
	cout << dp[0][n - 1] << endl;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repr(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define FORR(i, m, n) for (int i = (m); i >= (n); --i)
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll mod2 = 998244353;
const int INF = (1<<21);

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

  rep(i, n) {
    rep(j, n) {
      if (i == j) cnt[i][j] = 0;
      else cnt[i][j] = INF;
    }
  }

  FOR(l, 1, n) {
    rep(i, n-l) {
      int j = i+l;
      FOR(k, i, j) {
        cnt[i][j] = min(cnt[i][j], cnt[i][k] + cnt[k+1][j] + p[i] * p[k+1] * p[j+1]);
      }
    }
  }

  cout << cnt[0][n-1] << endl;



  
  return 0;
}