Go: package main

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

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	fmt.Println(resolve(parseProblem()))
}

type matrixSize struct{ row, col int }

func calcNum(i, j matrixSize) int {
	return i.row * j.col * i.col
}

func parseProblem() (int, []matrixSize) {
	n := scanInt(sc)
	sizes := make([]matrixSize, n)
	for i := 0; i < n; i++ {
		sizes[i] = matrixSize{row: scanInt(sc), col: scanInt(sc)}
	}
	return n, sizes
}

var dp [][]int

func initDP(n int) {
	dp = make([][]int, n+1)
	for i := 0; i < len(dp); i++ {
		dp[i] = make([]int, n+1)
		for j := 0; j < len(dp[i]); j++ {
			dp[i][j] = math.MaxInt64
		}
	}
}

func resolve(n int, sizes []matrixSize) int {
	// TODO 復習
	initDP(n)
	_rec(sizes, 0, n)
	return dp[0][n]
}

func _rec(sizes []matrixSize, l, r int) int {
	if dp[l][r] != math.MaxInt64 {
		return dp[l][r]
	}
	if r-l <= 1 {
		dp[l][r] = 0
		return 0
	}
	num := math.MaxInt64
	for i := l + 1; i < r; i++ {
		v := _rec(sizes, l, i) + _rec(sizes, i, r) + calcNum(matrixSize{sizes[l].row, sizes[i].row}, matrixSize{sizes[i].row, sizes[r-1].col})
		if v < num {
			num = v
		}
	}
	dp[l][r] = num
	return dp[l][r]
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define ll long long
using namespace std;

static const int N=100;

int main(){
    int n,p[N+1],m[N+1][N+1];
    cin>>n;
    for (int i=1;i<=n;i++) cin>>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;//長さ
            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;

    return 0;
}

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

static const int N = 100;

int main()
{
    int n, p[N + 1], m[N + 1][n + 1];
    cin >> n;
    for (int i = 1; i <= n; i++)
    {
        cin >> 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] = (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;

    return 0;
}

C++: // ALDS1_10_B Matrix Chain Multiplication
#include <iostream>
#include <vector>
#include <algorithm>
#include <utility>
#define INF 900000000
bool debug = false;
std::vector<std::vector<int>> dp;

void MatrixChainMultiplication(std::vector<std::pair<int,int>> sequence) {
    dp.resize(sequence.size());
    for (int i=0; i<dp.size(); i++) dp.at(i).resize(sequence.size());

    /*
    example:
        aN is a matrix. 
        ... a3 (a4 a5 a6)*(a7 a8) a9 ...
        i = 5, j = 4, k = 3
    */

    /* i = length of set */
    for (int i=2; i<dp.size(); i++) {
        /* j = front point */
        for (int j=1; j<=dp.at(i).size()-i; j++) {
            /* initialization of dp.at(i).at(j) */
            dp.at(i).at(j) = INF;
            /* k = dividing point */
            for (int k=1; k<i; k++) {
                if (i == 2) {
                    dp.at(i).at(j) = sequence.at(j).first*sequence.at(j).second*sequence.at(j+1).second;
                } else {
                    dp.at(i).at(j) = std::min(dp.at(i).at(j),
                                              dp.at(k).at(j)+dp.at(i-k).at(j+k)+sequence.at(j).first*sequence.at(j+k-1).second*sequence.at(i+j-1).second);
                    
                }
            }
            if (debug) {
                std::cout << "dp.at(" << i << ").at(" << j << ") = " << dp.at(i).at(j) << ":";
                for (int n=j; n<i+j; n++) std::cout << " " << n;
                std::cout << "\n";
            }
        }
    }
    std::cout << dp.back().at(1) << "\n";
}

int main() {
    int total; std::cin >> total;
    std::vector<std::pair<int,int>> sequence;
    sequence.resize(total+1);
    for (int i=1; i<sequence.size(); i++) {
        std::cin >> sequence.at(i).first >> sequence.at(i).second;
    }
    MatrixChainMultiplication(sequence);
}

C++: #include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
typedef float fl;
typedef long long ll;

static const int N = 100;

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

C++: #include <bits/stdc++.h>
using namespace std;
#define r(i,n) for(auto i=0;i<n;i++)
#define s(c) static_cast<int>((c).size())

int main(){
	int n;
	cin >> n;
	int i, t, A[n+1];
	cin >> A[0] >> A[1];
	for(i = 2; i <= n; i++){
		cin >> t >> A[i];
	}

	//dp[l][r] -> min(A[l]*...*A[r])
	int dp[n][n+1]{}, dplr, l, r;
	for(int i = 1; i <= n; i++){
		for(int j = 0; j < n-i; j++){
			l = j;
			r = j+i;
			dplr = INT_MAX;
			for(int k = l; k < r; k++){
				dplr = min(dplr, dp[l][k] + dp[k+1][r] + A[l]*A[k+1]*A[r+1]);
			}
			dp[l][r] = dplr;
			//printf("[%d, %d]=%d ", l, r, dplr);
		}
		//printf("\n");
	}

	printf("%d\n", dp[0][n-1]);
}

C++: #include<bits/stdc++.h>
using namespace std;
main(){
  int a[44],n;
  a[0]=a[1]=1;
  cin>>n;
  for(int i=2;i<=n;i++)a[i]=a[i-1]+a[i-2];
  cout<<a[n]<<endl; 
}

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

struct Mat{
	  int r,c;
};

int main(){

	  int n; cin >> n;
	  vector<Mat> Mats(n);
	  for(int i=0; i<n; i++)
			cin >> Mats[i].r >> Mats[i].c;

	  int dp[n][n] = {};
	  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] = INT_MAX;

	  for(int w=1; w<n; w++){
			for(int i=0; i+w<n; i++){
				  int j = i+w;
				  for(int k=i; k<j; k++){
						int num_prod = Mats[i].r * Mats[k+1].r * Mats[i+w].c;
						dp[i][i+w] = min(dp[i][i+w], dp[i][k] + dp[k+1][i+w] + num_prod);
				  }
			}
	  }
/*
	  for(int i=0; i<n; i++){
			for(int j=0; j<n; j++)
				  cout << dp[i][j] << " ";
			cout << endl;
	  }
*/	  
	  cout << dp[0][n-1] << endl;
	  
			
}