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
	}

	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
		}
	}
	memo[r] = minCount
	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>

#define rep(i, a, b) for (int i = a; i < (int)(b); ++i)
#define rrep(i, a, b) for (int i = b - 1; i >= (int)(a); --i)

using namespace std;

using ll = long long;
using vi = vector<int>;
using vii = vector<vi>;
using vll = vector<ll>;

int calc(vii& dp, const vector<pair<int, int>>& M, int i, int j) {
    if (i == j) { return 0; }
    if (dp[i][j] != 0) { return dp[i][j]; }

    int mul = M[i].first * M[j].second;
    int tmp = calc(dp, M, i + 1, j) + mul * M[i].second;
    rep(k, i + 1, j) {
        tmp = min(tmp, calc(dp, M, i, k) + calc(dp, M, k + 1, j) + mul * M[k].second);
    }
    return dp[i][j] = tmp;
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vector<pair<int, int>> M(n);

    rep(i, 0, n) {
        int x, y;
        cin >> x >> y;
        M[i] = make_pair(x, y);
    }

    vii dp(n, vi(n, 0));

    cout << calc(dp, M, 0, n - 1) << endl;

    return 0;
}

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

#define MAX 100

int n;
int p[MAX + 1];
int m[MAX + 1][MAX + 1];

int main() {
	cin >> n;
	cin >> p[0];
	for (int i = 1; i < n; i++)
		cin >> p[i] >> p[i];
	cin >> p[n];
	for (int i = 1; i <= n; i++)
		m[i][i] = 0;
	for (int l = 2; l <= n; l++) {
		for (int i = 1; i <= n - l + 1; i++) {
			int j = i + l - 1;
			m[i][j] = INT_MAX;
			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;
}

C++: #include <bits/stdc++.h>
using namespace std;
int n;
int cost(int i, int j, vector<vector<int>> &C, const vector<int> &p) {
  int min_cost = INT_MAX;
  if (C[i][j] != 0) return C[i][j];
  if (i == j) {
    min_cost = 0;
  } else if (i + 1 == j) {
    min_cost = p[i - 1] * p[i] * p[i + 1];
  } else {
    for (int k = j - 1; i < k; k--) {
      min_cost =
          min(cost(i, k, C, p) + cost(k + 1, j, C, p) + p[i - 1] * p[k] * p[j],
              min_cost);
    }
    C[i][j] = min_cost;
  }
  return min_cost;
}
int main() {
  int tmp;
  cin >> n;
  vector<int> p(n + 1);
  vector<vector<int>> C(n + 1, vector<int>(n + 1, 0));
  cin >> p[0];
  for (size_t i = 1; i <= n; i++) {
    cin >> p[i] >> tmp;
  }

  cout << cost(1, n, C, p) << endl;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

static const int N = 100;

int main(){
	int n, p[N + 1], m[N + 1][N + 1];
	cin >> n;
	for(int i=1;i<=n;i++){
		cin >> p[i - 1] >> p[i];
	}

	for(int i=1;i<=n;i++) m[i][i] = 0;
	for(int l=2;l<=n;l++){
		for(int i=1;i<=n-l+1;i++){
			int j=i+l-1;
			m[i][j] = (1 << 21);
			for(int k=i;k<=j-1;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;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdio>
#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] = 2000000000;
		}
	}
	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;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

static const in N = 100;

int main(){
  int j,i,l,n,p[N+1],m[N+1][N+1];
  scanf("%d",&n);

  for(i = 0;i<=n;i++){
    scanf("%d %d",&p[i-1],&p[i]);
  }

  for(i = 1; i<=n;i++) m[i][i] = 0;
  for(l=2;l<=n;l++){
    for(i=1;i<=n-l+1;i++){
      j = i+l-1;
      m[i][j] = (1<<21);
      for(int k = i; k <=j-1;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;
}

C++: #include <bits/stdc++.h>
using namespace std;
using ll = long long;
constexpr ll MOD = 1000000007;
constexpr ll INF = 1ll<<60;

template<class T>
bool chmin(T &a, T b)
{
	if (a > b)
	{
		a = b;
		return false;
	}
	return true;
}

template<class T>
bool chmax(T &a, T b)
{
	if (a < b)
	{
		a = b;
		return false;
	}
	return true;
}

template<class T>
bool chmax(T &a, initializer_list<T> l)
{
	return chmax(a, *max_element(l.begin(), l.end()));
}

template<class T>
bool chmin(T &a, initializer_list<T> l)
{
	return chmin(a, *min_element(l.begin(), l.end));
}

ll dp[110][110];
ll N;
ll P[110];
ll c{0};

ll solve(ll l, ll r)
{
	if (dp[l][r] != -1) return dp[l][r];
	
	//	if (c++ == 10) exit(-1);
	if (abs(l - r) <= 1) return dp[l][r] = 0;

	ll res{INF};
	for (ll mid = l+1; mid < r; ++mid)
	{
		chmin(res, solve(l, mid) + solve(mid, r) + P[l] * P[r] * P[mid]);
	}

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

int main(int argc, char **argv)
{
	cin >> N;
	for (ll i = 0;i < N; ++i)
		cin >> P[i] >> P[i+1];

	for (ll i = 0; i < 110; ++i) for (ll j = 0; j < 110; ++j) dp[i][j] = -1;
	std::cout << solve(0, N) << std::endl;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

static const int N = 100;

int main() {
  int n, p[N+1], m[N+1][N+1];
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> p[i-1] >> p[i];
  }

  // 同じindex、つまり行列1個の場合はコスト0
  for (int i = 1; i <= n; i++) m[i][i] = 0;
  // 計算する行列積の長さでループ
  for (int l = 2; l <= n; l++) {
    // 計算し始める行列の始点をずらす
    for (int i = 1; i <= n -l + 1; i++ ) {
      int j = i + l - 1;
      // 1 の 21bit左シフト。要するにinfty
      m[i][j] = (1 << 21);
      for (int k = i; k <= j - 1; 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;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

static const int N = 100;

int main(){
  int n,p[N + 1], m[N + 1][N + 1];
  cin >> n;
  for(int i = 1; i <=n; i++){
  cin >> p[i - 1] >> p[i];
 }

 for(int i = 1;i <=n; i++)m[i][i] = 0;
 for(int l = 2;l <=n; l++){
    for(int i = 1; i <= n - l + 1; i++){
    int j = i + l - 1;
    m[i][j] = (1 << 21);
    for(int k = i; k <= j - 1; 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;

   return0;
}