Submission #764177

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
764177	2023-06-23T08:19:04 Z	vjudge1	Exam (eJOI20_exam)	C++14	Compilation error	0 ms	0 KB

exam

// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define ordered_set tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>
#define len(x) (int)x.size()
#define ull unsigned long long
#define F first
#define S second
#define pb push_back
#define pf push_front
#define popb pop_back
#define popf pop_front
#define int long long

using namespace std;
using namespace __gnu_pbds;
using ll = long long;

const int N = 2e5 + 5;
const int MOD = 1e9 + 7;
int n,a[N],b[N],ans,c[N];

rec(int l = 0){
	int cnt = 0;
	for (int i=1;i<=n;i++){
		if (a[i]==b[i]) cnt++; 
	}
	ans = max(ans, cnt);
	for (int i=l+1;i<=n;i++){
		for (int j=i+1;j<=n;j++){
			int mx = 0;
			for (int k=i;k<=j;k++){
				mx = max(a[k],mx);
			}
			for (int k=i;k<=j;k++){
				c[k] = a[k];
				a[k] = mx;
			}
			rec(j + 1);
			for (int k=i;k<=j;k++){
				a[k] = c[k];
			}
		}
	}
}

main(){
	// freopen("txt.in", "r", stdin);
	// freopen("txt.out", "w", stdout);
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	cin >> n;
	for (int i=1;i<=n;i++){
		cin >> a[i];
	}
	for (int i=1;i<=n;i++){
		cin >> b[i];
	}
	rec();
	cout << ans;
}

//order_of_key(k): Number of items strictly smaller than k .
//find_by_order(k): K-th element in a set (counting from zero).

//sum of squares n*(n+1)*(2n+1)/6
//sum of cubes [n*(n+1)/2]^2
//sum of squares for odds n*(4*n*n-1)/3
//sum of cubes for odds n*n*(2*n*n-1)

//a/b%mod = a*(b^(m-2)%mod)
//(a>>x)&1 == 0
//a^b = (a+b)-2(a&b)

//srand(time(0))-always changing

Compilation message

exam.cpp:26:1: error: ISO C++ forbids declaration of 'rec' with no type [-fpermissive]
   26 | rec(int l = 0){
      | ^~~
exam.cpp: In function 'int rec(long long int)':
exam.cpp:48:1: warning: no return statement in function returning non-void [-Wreturn-type]
   48 | }
      | ^
exam.cpp: At global scope:
exam.cpp:50:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   50 | main(){
      | ^~~~