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 (r Range) length() int {
	return r.end - r.start + 1
}

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[r.start].r, matrices[r.end].c}, v
	}
	if r.length() == 0 {
		panic("must not be empty")
	} else if r.length() == 1 {
		return matrices[r.start], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < r.length()-1; i++ {
		formerRange := Range{r.start, r.start + i}
		latterRange := Range{r.start + i + 1, r.end}
		matF, countF := calcMinMatrixChainMultiplication(matrices, formerRange, memo)
		matL, countL := calcMinMatrixChainMultiplication(matrices, latterRange, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[r.start].r, matrices[r.end].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 <bits/stdc++.h>
using namespace std;

// 総数を1000000007で割った余り
const long long mod = 1e9 + 7;

using ll  = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define ull unsigned long long
#define ld long double
#define vi vector<int>
#define vll vector<ll>
#define vc vector<char>
#define vs vector<string>
#define vpii vector<pii>
#define vpll vector<pll>

#define rep(i, n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i, n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#define repr(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rep1r(i, n) for (int i = ((int)(n)); i >= 1; i--)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

#define SORT(v, n) sort(v, v + n);
// #define SORT(v, n) stable_sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));
#define pb push_back
#define mp make_pair

#define INF (1e9)
#define PI (acos(-1))
#define EPS (1e-7)

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }

static const int N = 100;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    // cout << fixed << setprecision(5);

    int n;
    cin >> n;
    int p[N + 1], m[N + 1][N + 1];
    rep1(i, n) { cin >> p[i - 1] >> p[i]; }
    rep1(i, n) 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;

const int INF = 1 << 30;
int n;
vector<int> r, c;
vector<vector<int>> dp;

int dfs(int a, int b) {
    if (dp[a][b] != INF) return dp[a][b];
    if (a + 1 == b) return dp[a][b] = 0;
    int res = INF;
    for (int k = a + 1; k < b; ++k) {
        res = min(res, dfs(a, k) + dfs(k, b) + r[a] * r[k] * c[b - 1]);
    }
    return dp[a][b] = res;
}

int main() {
    cin >> n;
    r.resize(n);
    c.resize(n);
    for (int i = 0; i < n; ++i) {
        cin >> r[i] >> c[i];
    }
    dp.resize(n + 1, vector<int>(n + 1, INF));
    cout << dfs(0, n) << endl;
}

C++: #include <iostream>
#include <string>
#include <sstream>
#include <list>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <vector>
#include <map>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <climits>
 
using namespace std;
 
int f(const int);
 
int main()
{
    int N;
    pair<int,int> data[100];
    vector<vector<int> > vdata(100,vector<int>(100,INT_MAX));
    cin>>N;
    for(int i=0;i<N;i++){
        cin>>data[i].first>>data[i].second;
    }
    vdata[0][0]=0;
    for(int j=1;j<N;j++){
        vdata[j][j]=0;
        for(int i=j-1;i>=0;i--){
            for(int k=i+1;k<=j;k++){
                int c=vdata[i][k-1]+vdata[k][j]+data[i].first*data[k].first*data[j].second;
                if(c<vdata[i][j]){
                    vdata[i][j]=c;
                }
            }
        }
    }
    cout<<vdata[0][N-1]<<endl;
}

C++: #include <iostream>

using namespace std;

int main() {
    int n;
    cin >> n;

    int dp[101][101];
    int N[101];
    for (int i = 1; i <= n; ++i) {
        cin >> N[i- 1] >> N[i];
    }

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

    for (int len = 2; len <= n ; ++len) {
        for (int i = 1; i <= n - len + 1; ++i) {
            int j = i + len - 1;
            dp[i][j] = (1 << 21);
            for (int k = i; k <= j - 1; ++k) {
                dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] + N[i - 1] * N[k] * N[j]);
            }
        }
    }

    cout << dp[1][n] << endl;
    return 0;
}

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

typedef long long lli;

const lli INF = 1LL << 59;
const int N = 1000;

int n;
vector<lli> v;

void solve(){
  lli dp[N][N];
  fill(dp[0],dp[N],INF);
  
  for(int i=0;i<=n;i++) dp[i][i] = 0;
  for(int i=2;i<=n;i++){
    for(int j=0;j+i-1<n;j++){
      int next = j + i - 1;
      for(int k=j;k<next;k++){
        dp[j][next] = min(dp[j][next], dp[j][k] + dp[k+1][next] + v[j] * v[k+1] * v[next+1]);
      }
    }
  }

  cout << dp[0][n-1] << endl;
}

int main(){
  while(cin >> n){
    v.clear();
    for(int i=0;i<n;i++) {
      int a,b;
      cin >> a >> b;
      if(i == 0) v.push_back(a);
      v.push_back(b);
    }
    solve();
  }
}

C++: #include <iostream>
#include <string.h>
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;
}