Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

// I/O
type Scanner struct {
	sc *bufio.Scanner
}

func NewScanner() *Scanner {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Buffer(make([]byte, 1024), int(1e+9))
	return &Scanner{sc}
}

func (s *Scanner) nextStr() string {
	s.sc.Scan()
	return s.sc.Text()
}

func (s *Scanner) nextInt() int {
	i, e := strconv.Atoi(s.nextStr())
	if e != nil {
		panic(e)
	}
	return i
}

func (s *Scanner) nextFloat() float64 {
	f, e := strconv.ParseFloat(s.nextStr(), 64)
	if e != nil {
		panic(e)
	}
	return f
}

func (s *Scanner) nextRuneSlice() []rune {
	return []rune(s.nextStr())
}

func (s *Scanner) nextIntSlice(n int) []int {
	res := make([]int, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextInt()
	}
	return res
}

func (s *Scanner) nextFloatSlice(n int) []float64 {
	res := make([]float64, n)
	for i := 0; i < n; i++ {
		res[i] = s.nextFloat()
	}
	return res
}

// Arithmetic
func max(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m < i {
			m = i
		}
	}
	return m
}

func min(nums ...int) int {
	m := nums[0]
	for _, i := range nums {
		if m > i {
			m = i
		}
	}
	return m
}

func abs(x int) int {
	if x > 0 {
		return x
	}
	return -x
}

func pow(x, y int) int {
	res := 1
	for i := 0; i < y; i++ {
		res *= x
	}
	return res
}

func ceil(a, b int) int {
	if a%b == 0 {
		return a / b
	} else {
		return a/b + 1
	}
}

// Sort
type RuneSlice []rune

func (a RuneSlice) Len() int           { return len(a) }
func (a RuneSlice) Less(i, j int) bool { return a[i] < a[j] }
func (a RuneSlice) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }

// Main
func main() {
	sc := NewScanner()
	wtr := bufio.NewWriter(os.Stdout)
	N := sc.nextInt()
	p := make([]int, N+1)
	dp := make([][]int, N+1)
	for i, _ := range dp {
		dp[i] = make([]int, N+1)
	}
	for i := 0; i < N; i++ {
		p[i] = sc.nextInt()
		p[i+1] = sc.nextInt()
	}
	for i := 1; i <= N; i++ {
		dp[i][i] = 0
	}
	for l := 2; l <= N; l++ {
		for i := 1; i <= N-l+1; i++ {
			j := i + l - 1
			dp[i][j] = 1 << 60
			for k := i; k <= j-1; k++ {
				dp[i][j] = min(dp[i][j], dp[i][k]+dp[k+1][j]+p[i-1]*p[k]*p[j])
			}
		}
	}

	fmt.Fprintln(wtr, dp[1][N])
	wtr.Flush()
}

C++: /**
 * 	matrix chain multiplication
 * 	f(n,m) = multiply Mn*M(n+1)*...*M(m-1)*M(m)
 * 	f(n,n) = 1
 * 	r(n)=c(n-1)
 * 	f(n,n+1) = C(n) * R(n) * C(n+1) = c(n) * c(n-1) * c(n+1)
 * 	f(n,k,m) = f(n,k)*f(k+1,m)*C(n)*r(n)*c(k)
 * 	f(n,m) = min(f(n,k,m)
 */

#include <iostream>
#include <cmath>
#include <climits>

using namespace std;

int r[45] = {0};
int a[100][100] = {0};

int f(int n, int m);
int f(int n, int k, int m);


int f(int n, int k, int m)
{
	return f(n,k) * f(k+1,m) + (r[n] * r[k+1] * r[m+1]);
}

int f(int n, int m)
{
	if (n==m) return 0;
	int & ra = a[n][m];
	if (ra) return ra;
	ra = INT_MAX;
	for (int k=n;k<m;k++)
	{
		int ans = f(n,k,m);
		if (ans < ra) ra = ans;
	}
	return ra;
}

int main()
{
	int rr = 0;
	int cc = 0;
	int n = 0;
	cin >> n;
	for (int i=0;i<n;i++)
	{
		cin >> rr >> cc;
		r[i]=rr;
		r[i+1]=cc;
	}
	for (int i=0;i<n-1;i++)
	{
		a[i][i+1] = r[i] * r[i+1] * r[i+2];
	}
	int ans = f(0,n-1);
	cout << ans << endl;
}

C++: #include <cmath>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <climits>
#include <map>
#include <list>
#include <stack>
#include <queue>
#include <vector>
#include <string>
#include <sstream>
#include <fstream>
#include <iostream>
#include <algorithm>
using namespace std;

int m[128], costs[128][128];
int calc(int s, int e){
	if(s==e) return 0;
	if(costs[s][e] != INT_MAX) return costs[s][e];
	return costs[s][e] = min(m[s-1] * m[s] * m[e] + calc(s+1, e), m[s-1] * m[e-1] * m[e] + calc(s, e-1));
}

int main() {
	int n;
	scanf("%d", &n);
	
	for(int i = 0; i < n; i++){
		scanf("%d %d", &m[i], &m[i+1]);
	}
	
	for(int i = 0; i <= n; i++){
		for(int j = 0; j <= n; j++){
			costs[i][j] = INT_MAX;
		}
	}
	
	printf("%d\n", calc(1, n));
	
	return 0;
}

C++: #include<iostream>


using namespace std;

#define N 100

int memo[N+1][N+1];
int q[N+1];

int main(){
  int n,i,j,k,l,min_memo;

  cin >> n;

  for(i=1;i<=n;i++) cin >> q[i-1] >> q[i];

  for(i=1;i<=n;i++) memo[i][i] = 0;

  for(l=2;l<n+1;l++){
    for(i=1;i<=n-l+1;i++){
      j = i +l -1;
      for(k = i;k<j;k++){
if(k==i) min_memo =  memo[i][k] + memo[k+1][j] + q[i-1]*q[k]*q[j];
    else  min_memo = min(min_memo, memo[i][k] + memo[k+1][j] + q[i-1]*q[k]*q[j]);
      }
      memo[i][j] =min_memo;
    }
  }

  cout << memo[1][n] << endl;

  return 0;
}

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";
}