Go: package main

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

type Matrix struct {
	r int // num of row
	c int // num of column
}

type Range struct {
	start int // index, inclusive
	end   int // index, inclusive
}

func calcMultiplication(x, y Matrix) (Matrix, int) {
	if x.c != y.r {
		panic("cannnot calculate")
	}
	return Matrix{x.r, y.c}, x.r * y.c * x.c
}

func calcMinMatrixChainMultiplication(matrices []Matrix, r Range, memo map[Range]int) (Matrix, int) {
	if v, ok := memo[r]; ok {
		return Matrix{matrices[0].r, matrices[len(matrices)-1].c}, v
	}
	if len(matrices) == 0 {
		panic("must not be empty")
	} else if len(matrices) == 1 {
		return matrices[0], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < len(matrices)-1; i++ {
		formerMatrices := matrices[:i+1]
		latterMatrices := matrices[i+1:]
		matF, countF := calcMinMatrixChainMultiplication(formerMatrices, Range{0, i}, memo)
		matL, countL := calcMinMatrixChainMultiplication(latterMatrices, Range{i + 1, len(matrices) - 1}, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[0].r, matrices[len(matrices)-1].c}, minCount
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, _ := nextInt(sc)
	matrices := make([]Matrix, n)
	for i := 0; i < n; i++ {
		r, _ := nextInt(sc)
		c, _ := nextInt(sc)
		matrices[i] = Matrix{r, c}
	}
	memo := make(map[Range]int)
	_, resultCount := calcMinMatrixChainMultiplication(matrices, Range{0, len(matrices) - 1}, memo)
	fmt.Println(resultCount)
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
static const int INFTY=2000000000;
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]=INFTY;
            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]);
        }
    }
    cout<<m[1][n]<<"\n";
    return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS

#include<iostream>
#include<functional>
#include<algorithm>
#include<stack>
#include<queue>
#include<iomanip>
#include<set>
#include<map>
#include<utility>
#include<string>
#include<vector>

using namespace std;

#define LL long long

LL n,dp[105][105]={},r[105],c[105];

LL solve(int L, int R){
	if(dp[L][R]!=0)return dp[L][R];
	if(L==R)return 0ll;
	if(R-L==1)return dp[L][R]=r[L]*c[L]*c[R];
	LL tmp=(1ll<<40);
	for(int i=L;i<R;i++)
		tmp=min(tmp,solve(L,i)+r[L]*r[i+1]*c[R]+solve(i+1,R));	
	return dp[L][R]=tmp;
	
}

int main() {
	cin>>n;
	for(int i=0;i<n;i++)cin>>r[i]>>c[i];
	cout<<solve(0,n-1)<<endl;
	return 0;
}

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

using namespace std;

const int N=110;

int a[N],dp[N][N];

int main()
{
    int n;

    scanf("%d",&n);

    for(int i=1;i<=n;i++) scanf("%d %d",&a[i],&a[i+1]);

    memset(dp,0x3f3f,sizeof(dp));

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

    for(int l=2;l<=n;l++)
    {
        for(int i=1;i+l<=n+1;i++)
        {
            int j=i+l-1;
            for(int k=i;k<j;k++)
            {
                dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]+a[i]*a[j+1]*a[k+1]);
            }
        }
    }

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

    return 0;
}

C++: #include <iostream>
#include <utility>
#include <vector>

using namespace std;

using VI = vector<int>;
using VVI = vector<VI>;
using P = pair<int, int>;

#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define IN(v) int v;cin>>v;
#define OUT(v) cout<<v<<endl
#define MOD 1000000007
#define INF 1000000000

vector<P> M;
VVI dp;
int solve(int start, int end) {
  if (dp[start][end] != INF)
    return dp[start][end];
  if (start + 2 == end)
    return dp[start][end] = dp[start][start+1] + dp[start+1][end] + M[start].first * M[start].second * M[start+1].second;
  int res = INF;
  for(int i = start; i + 1 != end; ++i) {
    res = min(res, solve(start, i + 1) + solve(i + 1, end) + M[start].first * M[i].second * M[end-1].second);
  }
  return dp[start][end] = res;
}
int main() {
  IN(N);
  dp.resize(N+1, VI(N+1, INF));

  REP(i, N) {
    IN(row);
    IN(column);
    M.push_back(make_pair(row, column));
    dp[i][i] = 0;
    dp[i][i+1] = 0;
  }
  OUT(solve(0, N));

  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>
using namespace std;

int n, a[100], v[101];
long sum, m = 1000000000;
bool f[100], g[100];

void permsum(int p) {
	if (p == n - 1) {
		sum = 0;
		memset(g, 0, 100);
		for (int i = 0; i < n - 1; i++) {
			g[a[i]] = 1;
			int u = 1, w = 1;
			while (g[a[i] - u])
				u++;
			while (g[a[i] + w])
				w++;
			sum += v[a[i] - u] * v[a[i]] * v[a[i] + w];			
		}
		if (m > sum)
			m = sum;
	}
	else {
		for (int j = 0; j < n - 1; j++) {
			if (!f[j]) {
				a[p] = j + 1;
				f[j] = 1;
				permsum(p + 1);
				f[j] = 0;
			}
		}
	}
}

int main()
{
	cin >> n;

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

	permsum(0);

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

	return 0;
}

C++: #include <iostream>
#include <cstdlib>
#include <string>
#include <typeinfo>
#include <cstring>
#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<stdio.h>
#include<iostream>
#include<algorithm>
using namespace std;

int main(){

    int n;
    scanf("%d", &n);

    int m[101][101], p[101];

    for(int i=1; i<=n; i++){
        int r, c;
        scanf("%d %d", &r, &c);
        p[i-1] = r; //これはなかなか思いつかない
        p[i] = c;
    }

    //行列の積になっていない
    for(int i=1; i<=n; i++) m[i][i] = 0; 
    //行列の積
    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]);
            }
        }
    }

    printf("%d\n", m[1][n]);
    return 0;
}