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 <bits/stdc++.h>
using namespace std;

//#define int long long
typedef long long ll;

typedef unsigned long long ul;
typedef unsigned int ui;
const ll mod = 1000000007;
const ll INF = mod * mod;
const int INF_N = 1e+9;
typedef pair<int, int> P;
#define stop char nyaa;cin>>nyaa;
#define rep(i,n) for(int i=0;i<n;i++)
#define per(i,n) for(int i=n-1;i>=0;i--)
#define Rep(i,sta,n) for(int i=sta;i<n;i++)
#define rep1(i,n) for(int i=1;i<=n;i++)
#define per1(i,n) for(int i=n;i>=1;i--)
#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)
#define all(v) (v).begin(),(v).end()
typedef pair<ll, ll> LP;
typedef long double ld;
typedef pair<ld, ld> LDP;
const ld eps = 1e-12;
const ld pi = acos(-1.0);
//typedef vector<vector<ll>> mat;
typedef vector<int> vec;

//繰り返し二乗法
ll mod_pow(ll a, ll n, ll m) {
	ll res = 1;
	while (n) {
		if (n & 1)res = res * a%m;
		a = a * a%m; n >>= 1;
	}
	return res;
}

struct modint {
	ll n;
	modint() :n(0) { ; }
	modint(ll m) :n(m) {
		if (n >= mod)n %= mod;
		else if (n < 0)n = (n%mod + mod) % mod;
	}
	operator int() { return n; }
};
bool operator==(modint a, modint b) { return a.n == b.n; }
modint operator+=(modint &a, modint b) { a.n += b.n; if (a.n >= mod)a.n -= mod; return a; }
modint operator-=(modint &a, modint b) { a.n -= b.n; if (a.n < 0)a.n += mod; return a; }
modint operator*=(modint &a, modint b) { a.n = ((ll)a.n*b.n) % mod; return a; }
modint operator+(modint a, modint b) { return a += b; }
modint operator-(modint a, modint b) { return a -= b; }
modint operator*(modint a, modint b) { return a *= b; }
modint operator^(modint a, int n) {
	if (n == 0)return modint(1);
	modint res = (a*a) ^ (n / 2);
	if (n % 2)res = res * a;
	return res;
}

//逆元(Eucledean algorithm)
ll inv(ll a, ll p) {
	return (a == 1 ? 1 : (1 - p * inv(p%a, a)) / a + p);
}
modint operator/(modint a, modint b) { return a * modint(inv(b, mod)); }

const int max_n = 1 << 18;
modint fact[max_n], factinv[max_n];
void init_f() {
	fact[0] = modint(1);
	for (int i = 0; i < max_n - 1; i++) {
		fact[i + 1] = fact[i] * modint(i + 1);
	}
	factinv[max_n - 1] = modint(1) / fact[max_n - 1];
	for (int i = max_n - 2; i >= 0; i--) {
		factinv[i] = factinv[i + 1] * modint(i + 1);
	}
}
modint comb(int a, int b) {
	if (a < 0 || b < 0 || a < b)return 0;
	return fact[a] * factinv[b] * factinv[a - b];
}
using mP = pair<modint, modint>;

int dx[4] = { 0,1,0,-1 };
int dy[4] = { 1,0,-1,0 };


ll p[105], dp[105][105];

void solve() {
    int n; cin >> n;
    rep1(i, n) cin >> p[i-1] >> p[i];

    Rep1(i, 0, n)Rep1(j, 0, n){
        if(i == j) dp[i][j] = 0;
        else dp[i][j] = INF;
    }

    Rep1(l, 2, n){
        Rep1(i, 1, n-l+1){
            int j = i + l - 1;
            Rep(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;
}

signed main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  //cout << fixed << setprecision(10);
  //init_f();
  //init();
  //int t; cin >> t; rep(i, t)solve();
  solve();
//   stop
    return 0;
}

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

using namespace std;

long minimum_product(const vector<int>& vec, int p, int q, vector<vector<int>>& dp){
    if(q-p <= 1){
        return 0;
    }
    if(dp[p][q]){
        return dp[p][q];
    }
    int ret = 2000000000;
    for(int i = p+1; i < q; ++i){
        int product = vec[p]*vec[q]*vec[i] + minimum_product(vec, p, i, dp)
                    + minimum_product(vec, i, q, dp);
        if(product < ret){
            ret = product;
        }
    }
    return dp[p][q] = ret;
}

int main(){
    vector<int> vec {};
    int n;
    cin >> n;
    for(int i = 0; i < n; ++i){
        int a, b;
        cin >>  a >> b;
        if(i == 0){
            vec.push_back(a);
        }
        vec.push_back(b);
    }
    vector<vector<int>> dp {n+1, vector<int>(n+1, 0)};
    cout << minimum_product(vec, 0, n, dp) << endl;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll=long long;
//const ll MOD=(ll)1e9+7;
const ll MOD=(ll)998244353;
const ll INF=(ll)1e18+10;
const double PI=acos(-1);

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 (a>b) { a=b; return 1; } return 0; }
int dy[]={-1,1,0,0};
int dx[]={0,0,-1,1};

ll dp[110][110];
int row[110],col[110];

ll dfs(int l, int r){
    if(r-l<=1) return 0;
    ll ret=INF;
    for(int i=l+1;i<r;++i){
        if(dp[l][i]==INF) dp[l][i]=dfs(l,i);
        if(dp[i][r]==INF) dp[i][r]=dfs(i,r);
        chmin(ret,dp[l][i]+dp[i][r]+row[l]*col[r-1]*row[i]);
    }
    return dp[l][r]=ret;
}

void solve(int ca){
    int N; cin>>N;
    for (int i = 0; i < N; ++i) {
        cin>>row[i]>>col[i];
    }
    for (int i = 0; i <= N; ++i) {
        for(int j=0;j<=N;++j) dp[i][j]=INF;
    }

    cout<<dfs(0,N)<<endl;

}

//#define MULTI
int main() {
#ifdef MULTI
    int N; cin>>N;
    for (int i = 0; i < N; ++i) {
        solve(i+1);
    }
#else
    solve(1);
#endif
    return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <algorithm>
using namespace std;
const int num = 105;
int p[num];
int main() {
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		scanf("%d%d", &p[i-1], &p[i]);
	}
	int m[num][num];
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			m[i][j] = 999999999999;
		}
	}
	for (int i = 1; i <= n; i++) m[i][i] = 0;
	for (int l = 1; l < n; l++) {
		for (int i = 1; i < n - l + 1; i++) {
			int j = i + l;
			for (int k = i; k < j; 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;
}