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
	} else if len(matrices) == 2 {
		return calcMultiplication(matrices[0], matrices[1])
	}

	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
		}
	}
	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 <stdio.h>
#include <stdint.h>
#include <iostream>
#include <fstream>
#include <cassert>
#include <climits>
using namespace std;

#define DEBUG (0)

#if DEBUG
#define DPRINTF(...) do { \
    printf("D(L%d) %s: ", __LINE__, __func__); \
    printf(__VA_ARGS__); \
  } while (false)
#else
#define DPRINTF(...)
#endif // DEBUG


struct Matrix {
  int numOfRow;
  int numOfColumn;
};


struct MinMatrix {
  int minMultiply;
  int numOfRow;
  int numOfColumn;
};


const int kMaxSize = 100;
const int kInvalid = -1;
MinMatrix minArrays[kMaxSize][kMaxSize];


bool isValid(MinMatrix mtx)
{
  return mtx.minMultiply != kInvalid ? true : false;
}

MinMatrix getMinScalarMultiply(const Matrix matrices[], int start, int end)
{
  DPRINTF("start %d  end %d\n", start, end);

  assert(start <= end);

  if (isValid(minArrays[start][end]))
    return minArrays[start][end];

  if (start + 1 == end)
  {
    MinMatrix mtx;

    mtx.minMultiply = 0;
    mtx.numOfRow = matrices[start].numOfRow;
    mtx.numOfColumn = matrices[start].numOfColumn;

    minArrays[start][end] = mtx;

    return minArrays[start][end];
  }


  MinMatrix minMtx;
  minMtx.minMultiply = INT_MAX;

  for (int i = start + 1; i < end; i++)
  {
    MinMatrix mtx0 = getMinScalarMultiply(matrices, start, i);
    MinMatrix mtx1 = getMinScalarMultiply(matrices, i, end);

    MinMatrix mtx;

    mtx.minMultiply = mtx0.minMultiply + mtx1.minMultiply + mtx0.numOfRow * mtx0.numOfColumn * mtx1.numOfColumn;
    mtx.numOfRow = mtx0.numOfRow;
    mtx.numOfColumn = mtx1.numOfColumn;

#if DEBUG
    DPRINTF("start %d  end %d  i %d : mtx.minMultiply %d  min.minMultiply %d\n",
        start, end, i, mtx.minMultiply, minMtx.minMultiply);
    DPRINTF("  mtx0.minMultiply %d  mtx1.minMultiply %d\n",
        mtx0.minMultiply, mtx1.minMultiply);
#endif

    if (minMtx.minMultiply > mtx.minMultiply)
      minMtx = mtx;
  }

  DPRINTF("start %d  end %d  multiply %d\n", start, end, minMtx.minMultiply);

  minArrays[start][end] = minMtx;

  return minArrays[start][end];
}


int calcMinScalarMultiply(const Matrix matrices[], int num)
{
  if (num <= 1)
    return 0;

  MinMatrix mtx = getMinScalarMultiply(matrices, 0, num);

  return mtx.minMultiply;
}


int main() {

  // init
  for (int i = 0; i < kMaxSize; i++)
    for (int j = 0; j < kMaxSize; j++)
      minArrays[i][j].minMultiply = kInvalid;

  int numOfMatrix;
  cin >> numOfMatrix; cin.ignore();

  Matrix  matrices[numOfMatrix];
  for (int i = 0; i < numOfMatrix; i++)
  {
    cin >> matrices[i].numOfRow; cin >> matrices[i].numOfColumn; cin.ignore();
  }

#if DEBUG
  for (int i = 0; i < numOfMatrix; i++)
  {
    DPRINTF("Matrix %d: %d %d\n", i, matrices[i].numOfRow, matrices[i].numOfColumn);
  }
#endif

  cout << calcMinScalarMultiply(matrices, numOfMatrix) << endl;

  return 0;
}

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


#define inf 1000000007

using namespace std;

int main(){
	int n;
	cin >> n;
	vector<pair<int,int> > m(n);
	for(int i=0;i<n;++i)cin >> m[i].first >> m[i].second;
	vector<vector<int> > dp;
	dp.resize(n);
	for(int i=0;i<n;++i){
		dp[i].resize(n);
		for(int j=0;j<n;++j)dp[i][j] = 0;
	}
	vector<int> p;
	for(int i=0;i<n;++i)p.push_back(m[i].first);
	p.push_back(m[n-1].second);
	for(int i=1;i<n;++i){
		for(int j=0;j+i<n;++j){
			dp[j][i+j] = inf;
			int t = i+j;
			for(int k=j+1;k<=t;++k){
				dp[j][t] = min(dp[j][t],dp[j][k-1]+dp[k][t]+p[j]*p[k]*p[t+1]);
			}
		}
	}
	cout << dp[0][n-1] << endl;
}

C++: /*
　　　∫ ∫ ∫
　　　ノヽ
　　（＿　 ）
　（＿　　　 ）
（＿＿＿＿＿＿ ）
　ヽ(´･ω･)ﾉ　
　　 |　 /
　　 UU
*/
#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
using P = pair<ll, ll>;
const int MOD = (int)1e9 + 7;
const ll INF = 1LL << 60;
const int inf = 1<<30;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define REP(i, n) for (int i = 0; i < (n); i++)
#define FOR(i,s,n) for (int i = s; i < (n); i++)
#define ALL(obj) (obj).begin(), (obj).end() //コンテナじゃないと使えない!!
#define debug(x) cerr << #x << ": " << x << "\n";
#define mp make_pair
template <typename T>
ostream& operator<<(ostream& os, vector<T> &V){
    int N = V.size();
    REP(i,N){
        os << V[i];
        if (i!=N-1) os << " ";
    }
    os << "\n";
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, pair<T,T> const&P){
    os << P.first;
    os << " ";
    os << P.second;
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, set<T> &S){
    auto it=S.begin();
    while(it!=S.end()){
        os << *it;
        os << " ";
        it++;
    }
    os << "\n";
    return os;
}
template <typename T>
ostream& operator<<(ostream& os, deque<T> &q){
    for(auto it=q.begin();it<q.end();it++){
        os<<*it;
        os<<" ";
    }
     os<<endl;
    return os;
}
//fixed<<setprecision(10)<<ans<<endl;
int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<int> A(N+1);
    REP(i,N){
        int a,b;
        cin >> a >> b;
        A[i]=a;
        A[i+1]=b;
    }

    int ans=0;
    vector<vector<int>> dp(N,vector<int>(N,inf));
    REP(i,N) dp[i][i]=0;

    for(int i=1;i<N;i++){
        for(int left=0;left<N-i;left++){
            int right = left+i;
            for(int k=0;k<i;k++){
                int mid = left+k;
                chmin(dp[left][right], dp[left][mid] + A[left]*A[mid+1]*A[right+1] + dp[mid+1][right] );
            }
        }
    }
    ans = dp[0][N-1];
    cout << ans << endl;
}