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 REP(i, n) for (int i = 0; i < n; i++)
#define ALL(obj) obj.begin(), obj.end()

template <class T>
inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}

const int iINF = 1e9;
const long long llINF = 1e18;
const int MOD = 1e9 + 7;

using namespace std;

int n;
int m[110][2], dp[110][110];

int rec(int l, int r) {
    if (dp[l][r] != -1) {
        return dp[l][r];
    }

    if (abs(l - r) <= 1) {
        return dp[l][r] = 0;
    }

    int res = iINF;

    if (abs(l - r) == 2) {
        return dp[l][r] = m[l][0] * m[l][1] * m[r - 1][1];
    }

    for (int mid = l + 1; mid < r; mid++) {
        res = min(
            res, rec(l, mid) + rec(mid, r) + m[l][0] * m[mid - 1][1] * m[r - 1][1]);
    }

    return dp[l][r] = res;
}

int main() {
    cin >> n;
    REP(i, n) {
        int r, c;
        cin >> r >> c;
        m[i][0] = r;
        m[i][1] = c;
    }

    memset(dp, -1, sizeof(dp));

    cout << rec(0, n) << endl;
    return 0;
}

C++: #include <iostream> 
#include <math.h> 
 
using namespace std; 
 
int r[45] = {0}; 
int a[100][100] = {0}; 
 
int f(int n, int m); 
int f(int n, int k, int m); 
 
 
int f(int n, int k, int m) 
{ 
    return f(n,k) * f(k+1,m) + (r[n] * r[k+1] * r[m+1]); 
} 
 
int f(int n, int m) 
{ 
    if (n==m) return 1; 
    int & ra = a[n][m]; 
    if (ra) return ra; 
    ra = INT_MAX; 
    for (int k=n;k<m;k++) 
    { 
        int ans = f(n,k,m); 
        if (ans < ra) ra = ans; 
    } 
    return ra; 
} 
 
int main() 
{ 
    int rr = 0; 
    int cc = 0; 
    int n = 0; 
    cin >> n; 
    for (int i=0;i<n;i++) 
    { 
        cin >> rr >> cc; 
        r[i]=rr; 
        r[i+1]=cc; 
    } 
    for (int i=0;i<n-1;i++) 
    { 
        a[i][i+1] = r[i] * r[i+1] * r[i+2]; 
    } 
    int ans = f(0,n-1); 
    cout << ans << endl; 
}

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

#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP0(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 RREP0(i,n) for(int i=n-1; i>=0; --i)
#define RREP1(i,n) for(int i=n; i>=1; --i)

#define SORT(c) sort((c).begin(),(c).end())
#define whole(f,x,...) ([&](decltype((x)) whole) { return (f)(begin(whole), end(whole), ## __VA_ARGS__); })(x)
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define CLR(a) memset((a), 0 ,sizeof(a))

inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}

typedef long long LL;
typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int, int> PII;

const int INTINF = 2147483647;
const LL LLINF = 9223372036854775807;
const double EPS = 1e-10;
const double PI  = acos(-1.0);

int gcd(int a,int b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};

static const int N = 100;



int main(int argc, char const *argv[]) {
  cin.tie(0); ios::sync_with_stdio(false);
  int n;
  int p[N+1]; //M_i が p[i-1]行 p[i]列 となる
  int m[N+1][N+1]; //M_i ~ M_jまでをかけあわせたときの最小の掛け算の数
  std::cin >> n;
  REP1(i,n) std::cin >> p[i-1] >> p[i];
  REP1(i,n) m[i][i]=0;

  FOR(l, 2, n){
    REP1(i, n-l+1){
      int j = i+l-1;
      m[i][j] = INTINF;
      FOR(k, i, j-1){
        m[i][j] = min(m[i][j], m[i][k] + m[k+1][j] + p[i-1]*p[k]*p[j]);
      }
    }
  }

  std::cout << m[1][n] << '\n';

  return 0;
}

C++: #include <iostream>
#include <limits>

constexpr int MAXN = 100;
int C[MAXN + 1][MAXN + 1];
int M[MAXN][2];

int main() {
    int n;
    std::cin >> n;
    for (int i = 0; i < n; i++) {
        std::cin >> M[i][0] >> M[i][1];
    }

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

    for (int j = 1; j < n; j++) {
        for (int i = j - 1; i >= 0; i--) {
            C[i][j] = std::numeric_limits<int>::max();
            for (int k = i; k < j; k++) {
                C[i][j] = std::min(C[i][j], C[i][k] + C[k+1][j] + M[i][0] * M[j][1] * M[k][1]);
            }
        }
    }
    std::cout << C[0][n-1] << std::endl;
}

C++: #include<algorithm>
#include<iostream>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
using namespace std;

typedef vector<int> VI;
typedef vector<VI> VVI;
typedef vector<string> VS;
typedef pair<int,int> PII;
typedef long long LL;

#define d(x)  cout<<#x<<" = "<<(x)<<endl;
#define ALL(a)  (a).begin(),(a).end()
#define RALL(a) (a).rbegin(), (a).rend()
#define PB push_back
#define MP make_pair
#define SZ(a) int((a).size())
#define EACH(i,c) for(typeof((c).begin()) i=(c).begin(); i!=(c).end(); ++i)
#define REACH(i,c) for(typeof((c).rbegin()) i=(c).rbegin(); i!=(c).rend(); ++i)
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define SORT(c,n) sort(c,c+n)
#define VSORT(c) sort((c).begin(),(c).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n)  FOR(i,0,n)
#define DFOR(i,b,a) for(int i=(b)-1;i>=(a);--i)
#define DREP(i,n) DFOR(i,n,0)
#define INF 2000000000

const double EPS = 1e-10;
const double PI  = acos(-1.0);
////////////////////////////////////////////////
int n,dp[110][110],p[110];


int main()
{
	cin>>n;
	FOR(i,1,n+1)
	{
		cin>>p[i-1]>>p[i];
	}
	FOR(i,1,n+1)
	{
		dp[i][i]=0;
	}
	FOR(l,2,n+1)
	{
		FOR(i,1,n-l+2)
		{
			int j=i+l-1;
			dp[i][j]=INF;
			FOR(k,i,j)
			{
				dp[i][j]=min(dp[i][j],dp[i][k]+dp[k+1][j]+p[i-1]*p[k]*p[j]);
			}
		}
	}
	cout<<dp[1][n]<<endl;
	return 0;
}