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<algorithm>
using namespace std;
void MatrixChain(int *p, int n, int **m, int **s)
{
	for (int i = 1;i <=n;i++)
		m[i][i] = 0;
	for (int r = 2;r <= n;r++)
	{
		for (int i = 1;i <= n - r + 1;i++)
		{
			int j = i + r - 1;
			m[i][j] = m[i + 1][j] + (p[i - 1] * p[i] * p[j]);
			s[i][j] = i;
			for (int k = i + 1;k < j;k++)
			{
				int t = m[i][k] + m[k + 1][j] + (p[i - 1] * p[k] * p[j]);
				if (t < m[i][j])
				{
					m[i][j] = t;
					s[i][j] = k;
				}
			}
		}
	}
}

void print(int i, int j, int **s)
{
	if (i == j)
		cout << "A" << i;
	else
	{
		cout << "(";
		print(i, s[i][j], s);
		print(s[i][j] + 1, j, s);
		cout << ")";
	}
}
int main()
{
	int n;
	cin >> n;
	int *tempP = new int[2 * n]; 
	int *p = new int[n + 1];   
	int **m = new int *[n + 1]; 
	int **s = new int *[n + 1]; 
	for (int i = 1; i <= n; i++)
	{
		m[i] = new int[n + 1];
		s[i] = new int[n + 1];
	}

	for (int i = 0; i < 2 * n; i++)
	{
		cin >> tempP[i];
	}

	for (int i = 0; i <= n; i++)
	{
		p[i] = (i == 0 ? tempP[0] : tempP[i * 2 - 1]);
	}
	MatrixChain(p, n, m, s);
	cout << m[1][n] << endl; 
	return 0;
}

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

int mcm(int p[], int n) {
	int m[n+1][n+1];
	memset(m, 0, sizeof(m));

	for (int s = 0; s < n; s++) {
		for (int i = 1, j = s + 2; j <= n; i++, j++) {
			m[i][j] = 1 << 30;
			for (int k = i; k <= j; k++) {
				m[i][j] = min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
			}
		}
	}
	return m[1][n];
}

int main() {
	int n, d;
	cin >> n;
	int p[n+1];
	for (int i = 0; i < n-1; i++) {
		cin >> p[i] >> d;
	}
	cin >> p[n-1] >> p[n];
	int ans = mcm(p, n);
	cout << ans << endl;
	return 0;
}

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

int convert(int p, int size, int n){
    for(int i=1;i<size;i++)p+=n--;
    return p;
}

int multipulication(int *r, int *c, int *count, int p, int size, int n){
    if(size==1)return 0;
    int id = convert(p,size,n);
    if(count[id])return count[id];
    int mlt = INT_MAX;
    int i, tmp;
    for(i=1;i<size;i++){
        tmp = r[p]*r[p+i]*c[p+size-1] + multipulication(r,c,count,p,i,n) + multipulication(r,c,count,p+i,size-i,n);
        if(tmp<mlt)mlt=tmp;
    }
    count[id] = mlt;
    return mlt;
}

int main(){
    int i, n;
    scanf("%d",&n);
    int r[n];
    int c[n];
    int count[n*(n+1)/2];
    for(i=0;i<n*(n+1)/2;i++)count[i]=0;
    for(i=0;i<n;i++)scanf("%d %d",r+i,c+i);
    printf("%d\n",multipulication(r,c,count,0,n,n));
    return 0;
}

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

#define MAX_N 10000
#define INF 10000000LL

long long n, j, x[MAX_N][MAX_N], p[MAX_N + 2];

int matrix() {
	for (int i = 0; i < n; i++) { x[i][i] = 0; }
	for (int h = 2; h <= n; h++) {
		for (int i = 1; i <= n - h + 1; i++) {
			j = i + h - 1;
			x[i][j] = INF;
			for (int k = i; k < j; k++) {
				x[i][j] = min(x[i][j], x[k + 1][j] + p[i - 1] * p[k] * p[j]);
			}
		}
	}
	return x[1][n];
}

int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		cin >> p[i - 1] >> p[i];
	}
	cout << matrix() << endl;
	return 0;
}

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 <stdlib.h>
#include <stdio.h>

int MCM(int n){
int i,j,k,l,m[101][101],p[101],x;

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]=10000000;
        for(k=i;k<=j;k++){
            x=m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j];
            if(m[i][j]>x)m[i][j]=x;
            }
        }
    }
return m[i-1][j];
}

int main(){

int i,n,m[101];

scanf("%d",&n);
for(i=0;i<n;i++){
    scanf("%d %d",&m[i],&m[i+1]);
   }
printf("%d\n",MCM(n));
return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
int main(){
	int n,a[101][101];
	int p[101];
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>p[i-1]>>p[i];
	}
	for(int i=1;i<=n;i++)a[i][i]=0;
	for(int l=2;l<=n;l++){
		for(int i=1;i<=n-l+1;i++){
			int j=i+l-1;
			a[i][j]=(1<<21);
			for(int k=i;k<=j-1;k++){
				a[i][j]=min(a[i][j],a[i][k]+a[k+1][j]+p[i-1]*p[k]*p[j]);
			}
		}
	}
	cout<<a[1][n]<<endl;
	return 0;
}