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>
#define fi first
#define se second
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rrep(i, n) for (int i = 1; i <= (n); ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define rng(a) a.begin(), a.end()
#define rrng(a) a.rbegin(), a.rend()
#define maxs(x, y) (x = max(x, y))
#define mins(x, y) (x = min(x, y))
#define limit(x, l, r) max(l, min(x, r))
#define lims(x, l, r) (x = max(l, min(x, r)))
#define isin(x, l, r) ((l) <= (x) && (x) < (r))
#define pb push_back
#define eb emplace_back
#define sz(x) (int)(x).size()
#define pcnt __builtin_popcountll
#define uni(x) x.erase(unique(rng(x)), x.end())
#define show(x) cout << #x << " = " << x << endl;
#define PQ(T) priority_queue<T, v(T), greater<T>>
#define bn(x) ((1 << x) - 1)
#define dup(x, y) (((x) + (y)-1) / (y))
#define newline puts("")
#define v(T) vector<T>
#define vv(T) v(v(T))
using namespace std;
typedef long long int ll;
typedef unsigned uint;
typedef unsigned long long ull;
typedef pair<int, int> P;
typedef tuple<int, int, int> T;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<P> vp;
typedef vector<T> vt;

ll dp[200][200];
template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
    std::fill( (T*)array, (T*)(array+N), val );
}

int main() { 
  int n;
  cin >> n;
  Fill(dp,INT_MAX);
  vl r(n+1),c(n);
  rep(i,n) cin >> r[i] >> r[i+1];
  rep(i,n) dp[i][i] = 0;
  

  for(int w = 1;w<n;w++){
    for(int i =0;i+w<n;i++){
      int j = i+w;
      for(int k=i;k<j;k++){
        ll prod = r[i]*r[k+1]*r[j+1];
        dp[i][j] = min(dp[i][j], dp[i][k]+dp[k+1][j]+prod);
      }
    }
  }
  cout<<dp[0][n-1]<<endl;
  return 0;
}

C++: #include <stdio.h>
#include <vector>
#include <list>
#include <map>
#include <array>
#include <memory>
#include <string>
#include <iostream>
#include <sstream>
#include <algorithm>
#include <cmath>
#include <unordered_map>
#include <stdexcept>


using std::string;
using std::vector;


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// util
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

std::vector<std::string> split(const std::string& input, char delimiter)
{
    std::istringstream stream(input);

    std::string field;
    std::vector<std::string> result;
    while (std::getline(stream, field, delimiter)) {
        result.push_back(field);
    }
    return result;
}



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// user func
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

void printList(const vector<int>& list) {
    // print
    for(int i = 0; i < list.size(); i++){
        printf(" %d", list[i]);
    }
    printf("\n");
}



//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// logic
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
typedef struct _Matrix {
    int row;
    int col;
} Matrix;

std::map<string, int> memo;
int GetCost(const vector<Matrix> list, int begin, int end)
{
    // printf("%d - %d\n", begin, end);
    if (begin == end) return 0;
    string hash = std::to_string(begin) + "," + std::to_string(end);
    if (memo[hash] != 0) return memo[hash];
    int min = std::numeric_limits<int>::max();
    for(int p = begin; p < end; p++){
        int r  = list[begin].row;
        int c1 = list[p].col;
        int c2 = list[end].col;
        int left = GetCost(list, begin, p);
        int right = GetCost(list, p + 1, end);
        min = std::min(min, left + right + r * c1 * c2);
        string lhash = std::to_string(begin) + "," + std::to_string(p);
        string rhash = std::to_string(p + 1) + "," + std::to_string(end);
        memo[lhash] = left;
        memo[rhash] = right;
        // min = std::min(min, GetCost(list, begin, p) + GetCost(list, p + 1, end) + r * c1 * c2);
    }
    return min;
}

void solve() {
    int n;
    scanf("%d", &n);
    vector<Matrix> matrixList(n);
    for(int i = 0; i < n; i++){
        int r, c;
        scanf("%d %d", &r, &c);
        matrixList[i] = {r,c};
    }
    int cost = GetCost(matrixList, 0, n - 1);
    printf("%d\n", cost);
}


//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// main
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
int main() {
    solve();
    return 0;
}

C++: /*
* @Author: Samson
* @Date:   2018-06-11 12:09:01
* @Last Modified by:   Samson
* @Last Modified time: 2018-06-11 15:37:51
*/
//   @URL : http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_10_B
#include<bits/stdc++.h>
#include<algorithm>
#include <cstdlib>
#define INF 0x3f3f3f3f
using namespace std;
typedef long long LL;
const int MAXN = 1e5+10;

int p[205],f[105][105];

int main(void)
{
	ios::sync_with_stdio(false); 
	//cin.tie(0);
	int n;
	cin>>n;
	for(int i = 1; i <= n; ++i)
		cin>>p[i-1]>>p[i];
	memset(f,INF,sizeof f);
	for(int i = 1; i <= n; ++i)	f[i][i] = 0;
	for(int i = 2; i <= n; ++i)
	{
		for(int l = 1; l <= n-i+1; ++l)
		{
			int r = i+l-1;
			f[l][r] = INF;
			for(int k = l; k <= r-1; ++k)
				f[l][r] = min(f[l][r], f[l][k]+f[k+1][r]+p[l-1]*p[k]*p[r]);
		}
	}
	cout<<f[1][n]<<'\n';
	return 0;
}