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<cmath>
#include<vector>

#define INF 1000000000

struct matrix {
	int row;
	int column;

};

using namespace std;

//leftはindexの添え字
int partprob_matchain(vector<vector<int>>& table, matrix* mat, int left, int right) {
	if (left == right) return 0;
	if (table.at(left).at(right) != 0) return table.at(left).at(right);
	int temp, min = INF;
	for (int i = left, j = left + 1; j <= right; i++, j++) {
		temp = partprob_matchain(table, mat, left, i);
		temp += partprob_matchain(table, mat, j, right);
		temp += mat[left].row * mat[i].column * mat[right].column;
		if (temp < min) min = temp;
	}
	table.at(left).at(right) = min;
	return min;
}


int matrix_chain(vector<vector<int>>& table, matrix* mat) {
	return partprob_matchain(table, mat, 0, table.at(0).size() - 1);
}


int main(void) {
	int size;
	cin >> size;
	matrix* mat = new matrix[size];
	vector<vector<int>> table(size, vector<int>(size));

	for (int i = 0; i < size; i++) cin >> mat[i].row >> mat[i].column;

	cout << matrix_chain(table, mat) << endl;
	delete[] mat;
	return 0;

}

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

inline int MIN(int a,int b){
	return ((a)<(b)?(a):(b));
}

int minimumProduct(int left, int right, vector<pair<int,int> >& mat, vector<vector<int> >& product) {
	if(left==right) return 0;
	if(product[left][right]!=-1) {
		return product[left][right];
	}
	int i,min=INT_MAX;
	for(i=left; i<right; ++i) {
		min=MIN(min,minimumProduct(left,i,mat,product)
				+minimumProduct(i+1,right,mat,product)
				+mat[left].first*mat[right].second*((i==right-1)?mat[right].first:mat[i].second));
	}
	return product[left][right]=min;
}

int main() {
	int n;
	int i,j;
	vector<pair<int,int> > mat;
	vector<vector<int> > product;

	scanf("%d",&n);
	mat.resize(n);
	product.resize(n);
	for(i=0; i<n; ++i) {
		product[i].resize(n);
		scanf("%d%d",&mat[i].first,&mat[i].second);
		for(j=0; j<n; ++j) {
			product[i][j]=-1;
		}
	}
	printf("%d\n",minimumProduct(0,n-1,mat,product));
	return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
const int MAXN = 100+7;

int p[MAXN];
int dp[MAXN][MAXN];
int n;
void generate_dp(){
    for(int i = 1; i <= n; i++){
        dp[i][i] = 0;
    }
    for(int b = 1; b < n; b++){
        for(int i = 1; i <= n-b; i++){
            int j = i+b;
            int k; k = i;
            int min_x = dp[i][k] + dp[k+1][j] + p[i-1]*p[k]*p[j];
            for(k = i+1; k < j; k++){
                if(dp[i][k] + dp[k+1][j] + p[i-1]*p[k]*p[j] < min_x){
                    min_x = dp[i][k] + dp[k+1][j] + p[i-1]*p[k]*p[j];
                }
            }
            dp[i][j] = min_x;
        }
    }
}
int main(){

    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        scanf("%d %d", &p[i], &p[i+1]);
    }
    generate_dp();
    printf("%d\n", dp[1][n]);

    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

typedef long long ll;

int main()
{
	ios_base::sync_with_stdio(0), cin.tie(0);

	int n;
	cin >> n;
	ll a, b;
	vector<pair<ll, ll>> v;
	for (int i = 0; i < n; ++i)
	{
		cin >> a >> b;
		v.push_back({a, b});
	}

	vector<vector<ll>> dp(n, vector<ll>(n, -1));
	function<ll(int, int)> f = [&](int i, int j)
	{
		if (i == j)
			return 0LL;

		if (dp[i][j] != -1)
			return dp[i][j];

		ll r = 1LL<<62;
		for (int k = i; k < j; ++k)
			r = min(r, f(i, k)+f(k+1, j)+v[i].first*v[j].second*v[k].second);

		return dp[i][j]=r;
	};

	cout << f(0, n-1) << "\n";

	return 0;
}

C++: #include <iostream>
using namespace std;
#define INF 200000000

int n,m[101],cm[101][101];

void calc(){
  int i,j,l,p,k;
  for (i=0;i<n;i++)cm[i][i]=0;
  for (l=1;l<n;l++){
    for(i=0;i<n-l;i++){
      j=i+l;
      cm[i][j]=INF;
      //cout << i << " "<< j << endl;
      for (k=i;k<j;k++){
	//cout << i << " "<< j <<" "<< k<<" "<<cm[i][k]<<" "<<cm[k+1][j] <<  endl;
	p=cm[i][k]+cm[k+1][j]+m[i]*m[k+1]*m[j+1];
	cm[i][j]=min(cm[i][j],p);
      }
    }
  }
}

int main(){
  cin >> n;
  for (int i=0;i<n;i++) cin >> m[i]>>m[i+1];

  calc();

  cout << cm[0][n-1]<<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[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
			}
		}
	}
	cout << m[1][n] << endl;
	return 0;
}