Go: package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"strconv"
)

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords) // bufio.ScanLines
	return sc
}

func main() {
	sc = initScanner(os.Stdin)
	fmt.Println(resolve(parseProblem()))
}

type matrixSize struct{ row, col int }

func calcNum(i, j matrixSize) int {
	return i.row * j.col * i.col
}

func parseProblem() (int, []matrixSize) {
	n := scanInt(sc)
	sizes := make([]matrixSize, n)
	for i := 0; i < n; i++ {
		sizes[i] = matrixSize{row: scanInt(sc), col: scanInt(sc)}
	}
	return n, sizes
}

var dp [][]int

func initDP(n int) {
	dp = make([][]int, n+1)
	for i := 0; i < len(dp); i++ {
		dp[i] = make([]int, n+1)
		for j := 0; j < len(dp[i]); j++ {
			dp[i][j] = math.MaxInt64
		}
	}
}

func resolve(n int, sizes []matrixSize) int {
	// TODO 復習
	initDP(n)
	_rec(sizes, 0, n)
	return dp[0][n]
}

func _rec(sizes []matrixSize, l, r int) int {
	if dp[l][r] != math.MaxInt64 {
		return dp[l][r]
	}
	if r-l <= 1 {
		dp[l][r] = 0
		return 0
	}
	num := math.MaxInt64
	for i := l + 1; i < r; i++ {
		v := _rec(sizes, l, i) + _rec(sizes, i, r) + calcNum(matrixSize{sizes[l].row, sizes[i].row}, matrixSize{sizes[i].row, sizes[r-1].col})
		if v < num {
			num = v
		}
	}
	dp[l][r] = num
	return dp[l][r]
}

// snip-scan-funcs
func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return int(i)
}
func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

C++: #include<bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (n) ; i++)
#define rrep(i,n) for(int i = n-1; i >= 0 ; i--)
constexpr auto INF = 2147483647;
typedef long long ll;

// void DebugGrid(int row, int column, auto table){
//   cout << endl;
//   rep(i,row){
//     rep(j,column) cout << table[i][j] << " ";
//     cout << endl;
//   }
// }

int main(){

  ll ans, n, DP[100][100];
  vector<pair<int,int>> matrix;
  cin >> n;
  rep(i,n){
    pair<int,int> inp;
    cin >> inp.first >> inp.second;
    matrix.emplace_back(inp);
  }

  rep(i,n)rep(j,n) DP[i][j] = INF;
  for(int l=0; l<n; l++)for(int i=0; i<n-l; i++){
    if(l == 0) DP[i][i] = 0;
    else{
      for(int j=i;j<=i+l;j++){
      DP[i][i+l] = min(DP[i][i+l],DP[i][j]+DP[j+1][i+l] + (matrix[i].first*matrix[j].second*matrix[i+l].second));
      }
    }
  }

  // DebugGrid(n,n,DP);
  cout << DP[0][n-1] << endl;
  return 0;
}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <set>
#include <string>
#include <queue>
#include <algorithm>
#include <map>
#include <cmath>
#include <numeric>
#include <list>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <tuple>

#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
#define show(a, n) rep(i,n) {cout<<a[i]<<' ';} cout<<endl;

using namespace std;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef long long ll;
typedef vector<ll> vll;
typedef pair<long long, long long> pll;

const int INF = 1 << 30;
const long long INFL = 1LL << 62;
const int MOD = 1000000007;
const int MAX = 100000;
const int N = 100010;

struct mat {
	ll r, c;
};

int main() {
//	cout << fixed << setprecision(15);
	int n;
	cin >> n;
	vector<mat> m(n);
	rep(i, n) cin >> m[i].r >> m[i].c;

	if(n == 1) {cout << 0 << endl; return 0; }

	vector<vll> dp(n, vll(n));
	rep(i, n) dp[i][i] = 0;
	int l, r;
	for(int d = 1; d <= n - 1; d++) {
		for(l = 0; l + d < n; l++) {
			r = l + d;
			dp[l][r] = INFL;
			for(int k = l; k + 1 <= r; k++) {
				dp[l][r] = min(dp[l][k] + dp[k + 1][r] + m[l].r * m[k].c * m[r].c, dp[l][r]);
			}
		}
	}
	cout << dp[0][n - 1] << endl;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define repr(i, n) for (int i = (n); i >= 0; --i)
#define FOR(i, m, n) for (int i = (m); i < (n); ++i)
#define FORR(i, m, n) for (int i = (m); i >= (n); --i)
using namespace std;
typedef long long ll;
const ll mod = 1000000007;
const ll mod2 = 998244353;
const int INF = (1<<21);

int main() {
  int n;
  cin >> n;
  int cnt[n][n];
  int p[n+1];
  rep(i, n) {
    cin >> p[i] >> p[i+1];
  }

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

  FOR(l, 1, n) {
    rep(i, n-l) {
      int j = i+l;
      FOR(k, i, j) {
        cnt[i][j] = min(cnt[i][j], cnt[i][k] + cnt[k+1][j] + p[i] * p[k+1] * p[j+1]);
      }
    }
  }

  cout << cnt[0][n-1] << endl;



  
  return 0;
}

C++: #include <bits/stdc++.h>
#define N 110
using namespace std;
int A[N];
int dp[N][N];

int Min(int &a,int b){return a = min(a,b);}
int main(){
  int n;
  cin>>n;

  for(int i=0,cnt=0;i<n;i++){
    int a,b;
    cin>>a>>b;
    if(i == 0) A[cnt++] = a;
    A[cnt++] = b;
  }

  for(int i=0;i<N;i++){
    for(int j=0;j<N;j++)dp[i][j] = 1e9;
    dp[i][i] = 0;
  }
  
  for(int len=0;len<n;len++)
    for(int l=1;l<n;l++){
      int r = l+len;
      for(int m = l;m<r;m++){
        Min(dp[l][r],dp[l][m] + dp[m+1][r] + A[l-1]*A[m]*A[r]);
      }
}
  
  cout<<dp[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];

	scanf("%d", &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]);
				}
			}
		}

		printf("%d\n", m[1][n]);

		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;
    
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

int main() {
    int n; 
    cin >> n; 
    int r, c;
    vector<pair<int, int>> v; 
    vector<int> dims; 
    for (int i = 0; i < n; ++i) { 
            cin >> r >> c; 
            if (i == 0) { 
                dims.push_back(r);
            } 
        dims.push_back(c);
    }
    // for (int i = 0; i < dims.size(); ++i)
    //     cout << dims[i] << " ";
    int dp[n][n];
    for (int i = 0; i < n; ++i)
        for (int j = 0; j < n; ++j)
            dp[i][j] = 0;
    
    for (int len = 2; len <= n; ++len) { 
        for (int i = 0; i <= n - len; ++i) { 
            int j = i + len-1;
            // cout << i << " " << j <<" -> ";
            dp[i][j] = INT_MAX;
            for (int k = i; k < j; ++k) { 
                // cout << dp[i][k] << " " << dims[i] << " " << dims[k+1] << " " << dims[j+1] << endl;
               int q = dp[i][k] + dp[k+1][j] + dims[i]*dims[k+1]*dims[j+1]; 
               dp[i][j] = min(q, dp[i][j]);
            }
        }
    }
    // for (int i = 0; i < n; ++i) {
    //     for (int j = 0;j < n; ++j)
    //         cout << dp[i][j] << " ";
    //     cout << endl;
    // }
    cout << dp[0][n-1] << endl;
   
}