Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

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

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list {
		buf.Write([]byte(fmt.Sprintf(" %d", v)))
	}
	buf.Write([]byte("\n"))
	buf.Flush()
}

//solve
//単純な場合
func matrixChainMultiplication() {
	//行列が1つだけのとき
	for i := 1; i <= n; i++ {
		m[i][i] = 0
	}
	for l := 2; l <= n; l++ {
		for i := 1; i <= n-l+1; i++ {
			j := i + l - 1
			m[i][j] = 1 << 21
			//kまでで区切る
			for 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])
			}
		}
	}
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

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

const MAX = 100

var n int
var p [MAX + 1]int

//m[i][j]: Mi * Mi+1 * ... * Mjを計算するときに必要なスカラー乗算の最小回数
var m [MAX + 1][MAX + 1]int

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 1; i <= n; i++ {

		p[i-1] = nextInt() //行数
		p[i] = nextInt()   //列数
	}

	matrixChainMultiplication()
	fmt.Println(m[1][n])
}

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

struct Matrix {
	int r,c;
};

long f(vector<Matrix> &m, int begin, int end) {
	if (m.size() < 2 || (end - begin) < 2) return 0;
	if ((end - begin) == 2) {
		return m[begin].r * m[begin].c * m[begin+1].c;
	}
	long common = m[begin].r * m[end-1].c;
	long res	= common * m[begin+1].r + f(m,begin+1,end);
	for (int i=2;i<(end-begin);++i) {
		long t = f(m,begin, begin+i) + f(m,begin+i,end) + common * m[begin+i].r;
		res = min(res, t);
	}
	return res;
}

int main() {
	int n;
	cin >> n;
	vector<Matrix> M(n);
	for (int i=0;i<n;++i) {
		int r,c;
		cin >> r >> c;
		M[i].r = r; M[i].c = c;
	}
	cout << f(M, 0, M.size()) << 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++: #include <iostream>
#include <array>
#include <limits>

using namespace std;

struct MatrixDims {
    int row;
    int col;
    MatrixDims() {}
    MatrixDims(int row, int col) : row(row), col(col) {}
};

array<MatrixDims, 100> matrix_dims;
array<array<int, 100>, 100> dp;

int get_min(int row, int col) {
    int min = numeric_limits<int>::max();
    for (int j = row; j < col; ++j) {
        int sum = dp[row][j] + dp[j+1][col] + matrix_dims[row].row * matrix_dims[j].col * matrix_dims[col].col;
        if (sum < min) min = sum;
    }
    return min;
}

int main()
{
    int n;
    cin >>  n;
    for (int i = 0; i < n; ++i) {
        int row, col;
        cin >> row >> col;
        matrix_dims[i] = MatrixDims(row, col);
    }
    dp.fill({});
    
    for (int endpt = 1; endpt < n; ++endpt) {
        for (int diag_i = 0; (endpt + diag_i) < n; ++diag_i) {
            dp[diag_i][diag_i + endpt] = get_min(diag_i, endpt + diag_i);
        }
    }
    cout << dp[0][n-1] << endl;
}

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];  // pは行と列を入れる配列，mは行列の計算回数を入れる配列
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> p[i - 1] >> p[i];  // 行と列を入れている
    }

    for (int i = 1; i <= n; i++) {
        m[i][i] = 0;  // 対角成分を初期化する(同じ行列同士をかける場所だから)
    }
    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 <stdio.h>

int n;
int r[100], c[100];
int dp[101][101];

int main(void)
{
	int i, j, w, m;
	
	for (i = 0; i < 101; i++){
		for (j = 0; j < 101; j++){
			dp[i][j] = 1 << 28;
		}
	}
	for (i = 0; i < 100; i++){
		dp[i][i + 1] = 0;
	}
	
	scanf("%d", &n);
	for (i = 0; i < n; i++){
		scanf("%d %d", &r[i], &c[i]);
	}
	
	for (w = 2; w <= n; w++){
		for (i = 0; i + w <= n; i++){
			for (m = i + 1; m < i + w; m++){
				if (dp[i][i + w] > dp[i][m] + dp[m][i + w] + r[i] * r[m] * c[i + w - 1]){
					dp[i][i + w] = dp[i][m] + dp[m][i + w] + r[i] * r[m] * c[i + w - 1];
				}
			}
		}
	}
	
	printf("%d\n", dp[0][n]);
}

C++: #include<cstdio>
#include<cstring>

int r[105];
int c[105];
int cache[105][105];

int f(int a, int b){
	if(a==b)
		return 0;
	if(cache[a][b] == -1)
	{
		cache[a][b] = 1000000000; 
		for(int i = a; i<b; i++){
			int res = f(a,i) +f(i+1, b) +r[a]*c[i]*c[b];
			if(res<cache[a][b])
				cache[a][b] = res;
		}
	}
	return cache[a][b];
	
}

int  main(){
	int n;
	scanf("%d",&n);
	for(int i = 0; i<n; i++){
		scanf("%d %d",&r[i], &c[i]);	
	}
	memset(cache, -1, sizeof(cache));
	printf("%d\n",f(0,n-1));
}

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


static const int N = 100;

int m[N+1][N+1];
int main()
{
    int n,p[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;
    int i;
    for(int l=2;l<=n;l++)
    {
        for(int i=1;i<=n-l+1;i++)
        {
            int j=i+l-1;
            m[i][j]=(9999999);
            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 << "l i j k m[i][j]:" <<l<<" " << i << " " << j << " "<<k<<" "<<m[i][j]<<endl;
            }
        }
    }
    cout <<m[1][n] << endl;

    return 0;
}

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

struct Matrix{
  int x, y;
};

int dp[111][111];
vector<Matrix> v;
Matrix matrix[111][111];

int main(){

  int n, r, c;

  cin >> n;

  for(int i = 0; i < n; i++){
    cin >> r >> c;
    v.push_back((Matrix){r,c});
  }

 
  for(int i = 0; i < n; i++) dp[i][i] = 0;
  for(int i = 1; i < n; i++){
    for(int j = 0; j < n - i; j++){
      int s = j + i;
      dp[j][s] = INT_MAX;
      for(int l = j; l < s; l++){
	dp[j][s] = min(dp[j][s],dp[j][l] + dp[l+1][s] + v[j].x * v[s].y * v[l].y);
      }
    }
  }
  cout << dp[0][n-1] << endl;
 }

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;
}