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;

template<class T> inline void chmin(T &a, const T &b) { if(a > b) a = b; }

int mul(const int r1, const int c1, const int r2, const int c2) {
	assert(c1 == r2);
	return r1 * c2 * r2;
}

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

	vector<int> R(n), C(n);
	for(int i = 0; i < n; ++i) {
		cin >> R[i] >> C[i];
	}

	constexpr int INF = (1 << 29);
	vector<vector<int>> dp(n, vector<int>(n + 1, INF));
	for(int i = 0; i < n; ++i) {
		dp[i][i + 1] = 0;
	}

	for(int len = 0; len <= n; ++len) {
		for(int l = 0; l + len <= n; ++l) {
			const int r = l + len;
			for(int i = l + 1; i < r; ++i) {
				chmin(dp[l][r], dp[l][i] + dp[i][r] + mul(R[l], C[i - 1], R[i], C[r - 1]));
			}
		}
	}

	cout << dp[0][n] << endl;

	return EXIT_SUCCESS;
}

C++: #include<bits/stdc++.h>
using namespace std;
#define MAXN 102
#define INF 10000000
int dp[MAXN][MAXN];
int p[MAXN];
int main(){
    int n;
    scanf("%d", &n);
    scanf("%d", p);
    int x;
    for(int i = 1; i < n; i++)
        scanf("%d%d", &x, p + i);
    scanf("%d", p + n);
    for(int i = 1; i <= n; i++)
        dp[i][i] = 0;
    for(int l = 1; l < n; l++){
        for(int i = 1; i + l <= n; i++){
            int j = i + l;
            dp[i][j] = INF;
            for(int k = i; k < j; k++){
                dp[i][j] = min(dp[i][j], dp[i][k] + dp[k + 1][j] + p[i - 1] * p[k] * p[j]);
            }
        }
    }
    printf("%d\n", dp[1][n]);
    return 0;
}

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

using namespace std;

#define INF 1e9

int main(){
  int n;

  cin >> n;
  vector<int> r(n),c(n),p;
  for(int i = 0 ; i < n ; i++){
    cin >> r[i] >> c[i];
  }

  p.push_back(r[0]);
  for(int i = 0 ; i < n ; i++){
    p.push_back(c[i]);
  }

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

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

  cout << dp[1][n] << endl;

  return 0;
}

C++: #include "bits/stdc++.h"
 
using namespace std;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<VVI> VVVI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef vector<PII> VPII;
typedef long long LL;
typedef priority_queue<int> PQ_DESC;
typedef priority_queue<int, vector<int>, greater<int>> PQ_ASC;
typedef priority_queue<PII> PQ_DESC_PII;
typedef priority_queue<PII, vector<PII>, greater<PII>> PQ_ASC_PII;
typedef vector<LL> VLL;
typedef vector<VLL> VVLL;
typedef vector<VVLL> VVVLL;

#define SORT_ASC(c) sort((c).begin(), (c).end())
#define SORT_DESC(c) sort((c).begin(), (c).end(), greater<typeof((c).begin())>())
 
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define FORL(i,a,b) for(LL i=(a);i<(b);++i)
#define REPL(i,n)  FORL(i,0,n)
#define ALL(a) (a).begin(),(a).end()
 
const double EPS = 1e-10;
const double PI  = acos(-1.0);

 //debug func
template<typename T>
void vprint(vector<T> v) {
    for(auto x : v) {
        cerr << x << " ";
    }
    cerr << endl;
}
 
template<typename T>
void vvprint(vector<vector<T>> vv) {
    REP(i, vv.size()) {
        REP(j, vv[i].size()) {
            cerr << vv[i][j] << " ";
        }
        cerr << endl;
    }
}

template <typename Iterator>
inline bool next_combination(const Iterator first, Iterator k, const Iterator last)
{
   /* Credits: Thomas Draper */
   if ((first == last) || (first == k) || (last == k))
      return false;
   Iterator itr1 = first;
   Iterator itr2 = last;
   ++itr1;
   if (last == itr1)
      return false;
   itr1 = last;
   --itr1;
   itr1 = k;
   --itr2;
   while (first != itr1)
   {
      if (*--itr1 < *itr2)
      {
         Iterator j = k;
         while (!(*itr1 < *j)) ++j;
         iter_swap(itr1,j);
         ++itr1;
         ++j;
         itr2 = k;
         rotate(itr1,j,last);
         while (last != j)
         {
            ++j;
            ++itr2;
         }
         rotate(k,itr2,last);
         return true;
      }
   }
   rotate(first,k,last);
   return false;
}

inline double get_time_sec(void){
    return static_cast<double>(chrono::duration_cast<chrono::nanoseconds>(chrono::steady_clock::now().time_since_epoch()).count())/1000000000;
}

template<typename T>
T lcm(T a, T b) {
    return (a / __gcd(a, b)) * b;
}

template<typename T>
map<T, T> prime_list(T n) {
    map<T, T> ret;
    for(T i = 2; i*i <= n; i++) {
        if(n % i == 0) {
            ret[i] = 0;
            while(n % i == 0) {
                n /= i;
                ret[i]++;
            }
        }
    }
    if(n != 1) ret[n]++;
    return ret;
}

#define MOD 1000000007

LL mypow(LL a, LL n) {
    if(n == 0) return 1;
    if(n == 1) return a % MOD;
    if(n % 2 == 1) return (a * mypow(a, n-1)) % MOD;
    LL t = mypow(a, n/2);
    return (t * t) % MOD; 
}

LL mycomb(LL n, LL k) {
    if(n == 0 || n == k) return 1;
    LL x = 1, y = 1;
    REP(i, k) {
        x = x * (n-i) % MOD;
        y = y * (i+1) % MOD;
    }
    return x * mypow(y, MOD - 2) % MOD;
}

#define INF 1e8

int main(void) {
    cin.tie(0); ios::sync_with_stdio(false);
    int n;
    cin >> n;
    VI vr(n), vc(n);
    REP(i, n) cin >> vr[i] >> vc[i];
    VVI dp(n, VI(n, 0));
    REP(i, n-1) dp[i][i+1] = vr[i] * vr[i+1] * vc[i+1];
    FOR(w, 2, n) {
        REP(l, n) {
            int r = l + w;
            if(r >= n) continue;
            int tmp = INF;
            FOR(mid, l, r) tmp = min(tmp, dp[l][mid] + dp[mid+1][r] + vr[l] * vc[mid] * vc[r]);
            dp[l][r] = tmp;
        }
    }
    // vvprint(dp);
    cout << dp[0][n-1] << endl;
}

C++: #include <bits/stdc++.h>
#define r(i,n) for(int i=0;i<n;i++)
using namespace std;
int dp[111][111],n,L[111],R[111];

int dfs(int l,int r){
	if(dp[l][r]!=-1)return dp[l][r];
	int res=1e9;
	for(int i=l;i<r;i++){
		res=min(res,dfs(l,i)+dfs(i+1,r)+L[l]*R[i]*R[r]);
	}
	return dp[l][r]=res;
}

signed main(){
	memset(dp,-1,sizeof(dp));
	r(i,111)dp[i][j]=0;
	cin>>n;
	r(i,n)cin>>L[i]>>R[i];
	cout<<dfs(0,n-1)<<endl;
}