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 <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int maxx = 110;
const int INF = 1 << 30;
int main()
{
	int n, p[maxx], m[maxx][maxx];

	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 - l + 1; i++) {
			int j = i + l - 1;
			m[i][j] = INF;
			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 <stdio.h>
#include <algorithm>
using namespace std;
int n, r[100], c[100], dp[100][101];
int main() {
	scanf("%d", &n);
	for(int i = 0; i < n; i++) scanf("%d%d", &r[i], &c[i]), dp[i][i] = 0;
	for(int i = 1; i <= n; i++) {
		for(int j = 0; i + j <= n; j++) {
			dp[j][i + j] = min(dp[j][i + j - 1], dp[j + 1][i + j]) + r[j] * c[i + j - 1];
		}
	}
	printf("%d\n", dp[0][n]);
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <map>
#define MAX_NUM 100
#define INFTY 1000000000
#define NIL -1

using namespace std;

//think easy make easy

int n;//num of input


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

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(map[s,e] != NIL)
		return map[s,e];

	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;
	}
	map[s,e] = min_time;//メモ
	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
	}
	for(int i=0;i<n;i++){
		for(int j=i;j<n;j++){
			map[i][j] = NIL;
		}
	}

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

	return 0;
}

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

int m[105][105];
int plen;
//function matrix chain order
void matrixco(int p[]){
  int n,j,q;
  n=plen-1;
  for(int i=1;i<=n;i++){
    m[i][i]=0;
  }

  for(int l=2;l<=n;l++){
    for(int i=0;i<=n-l+1;i++){
      j=i+l-1; 
      m[i][j]=INT_MAX;   
      for(int k=i;k<=j-1;k++){
	q=m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j];
	if(q<m[i][j]){
	  m[i][j]=q;
	}
      }
    }
  }
}

int main(){
  int n;
  int p[105];
  int r,c;
  //load n
  cin >>n;

  plen=n+1;

  for(int i=0;i<n;i++){
    //load r,c
    scanf("%d %d",&r,&c);

    if(i!=n-1) p[i]=r;
    else{
      p[i]=r;
      p[i+1]=c;
    }
  }

  matrixco(p);

  cout <<m[1][n]<<endl;
  return 0;
}

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

typedef long long ll;
const ll inf = 1<<30;

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

    int nb; cin >> nb;
    vector<ll> dim(nb);
    int trash;
    for(auto& a:dim) cin >> a >> trash;
    dim.push_back(trash);
    
    vector<vector<ll>> cost( nb, vector<ll>(nb, inf) );
    for (int i=0; i<nb; ++i){
        cost[i][i] = 0;
    }
    
    for (int k=1; k<nb; ++k){
        for (int i=0; i+k<nb; ++i){
            for (int j=0; j<i+k; ++j){
                cost[i][i+k] = min(
                    cost[i][i+k],
                    cost[i][j] + cost[j+1][i+k] + dim[i]*dim[j+1]*dim[i+k+1]);
            }
        }
    }

    cout<<cost[0][nb-1] <<"\n";
}

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

int main(void){
    int i,n;
    cin >> n;
    int p[n+1];
    int **m = new int*[n+1];
    for(i=1; i<=n; i++){
        m[i] = new int[n+1];
    }
    for(i=1; i<=n; i++) cin >> p[i-1] >> p[i];
    for(i=1;i<=n;i++) m[i][i] = 0;
    for(int l=2; l<=n; l++){
        for(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;
    for(int i=1; i<n+1; i++){
        delete[] m[i];
        m[i] = 0;
    }
    delete[] m;
    m = 0;
    return 0;
}