Submission #1158046

#	Time	Username	Problem	Language	Result	Execution time	Memory
1158046		SmuggingSpun	Cat Exercise (JOI23_ho_t4)	C++20	0 / 100	0 ms	332 KiB

Main

#include<bits/stdc++.h>
#define taskname "C"
using namespace std;
const int lim = 2e5 + 5;
int n, P[lim], A[lim], B[lim];
namespace sub123{
	void solve(){
		vector<vector<int>>f(n + 1, vector<int>(n + 1, -1)), p(n + 1, vector<int>(n + 1));
		for(int i = 1; i <= n; i++){
			p[i][i] = i;
			for(int j = i + 1; j <= n; j++){
				p[i][j] = (P[j] > P[p[i][j - 1]] ? j : p[i][j - 1]);
			}
		}
		function<int(int, int)>dp;
		dp = [&] (int l, int r){
			if(l > r){
				return 0;
			}
			int& ans = f[l][r];
			if(ans != -1){
				return ans;
			}			
			int i = p[l][r];
			return ans = max(dp(l, i - 1), dp(i + 1, r)) + 1;
		};
		cout << dp(1, n);
	}
}
namespace sub4567{
	void solve(){

	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> P[i];
	}
	bool is_sub123 = true;
	for(int i = 1; i < n; i++){
		cin >> A[i] >> B[i];
		if(A[i] != i && B[i] != i + 1){
			is_sub123 = false;
		}
	}
	if(n <= 5000 && is_sub123){
		sub123::solve();
	}
	else{
		sub4567::solve();
	}
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:38:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 7
• Subtask 4: 0 / 10
• Subtask 5: 0 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26