Submission #1150640

#	Time	Username	Problem	Language	Result	Execution time	Memory
1150640		SmuggingSpun	Palindromes (APIO14_palindrome)	C++20	0 / 100	0 ms	324 KiB

palindrome

#include<bits/stdc++.h>
#define taskname "A"
using namespace std;
typedef long long ll;
template<class T>void maximize(T& a, T b){
	if(a < b){
		a = b;
	}
}
string s;
ll ans = 0;
struct Node{
	int link, len, cnt, child[26];
	Node(){
		memset(this->child, -1, sizeof(this->child));
		this->cnt = 0;
	} 
};
vector<Node>eer(2);
void dfs(int s){
	for(int i = 0; i < 26; i++){
		if(eer[s].child[i] != -1){
			dfs(eer[s].child[i]);
		}
	}
	eer[eer[s].link].cnt += eer[s].cnt;
	maximize(ans, 1LL * eer[s].cnt * eer[s].len);
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	eer[eer[1].len = eer[0].link = eer[1].link = 0].len = -1;
	cin >> s;
	for(int i = 0, root = 0; i < s.size(); i++){
		s[i] -= 97;
		while(i - eer[root].len < 1 || s[i] != s[i - eer[root].len - 1]){
			root = eer[root].link;
		}
		if(eer[root].child[s[i]] == -1){
			int cur = eer[root].child[s[i]] = eer.size();
			eer.emplace_back(Node());
			if((eer[cur].len = eer[root].len + 2) > 1){
				int r = root;
				while(true){
					if(i - eer[r = eer[r].link].len > 0 && s[i - eer[r].len - 1] == s[i]){
						eer[cur].link = eer[r].child[s[i]];
						break;
					}
				}
			}
			else{
				eer[cur].link = 0;
			}
		}
		eer[root = eer[root].child[s[i]]].cnt++;
	}
	dfs(0);
	dfs(1);
	cout << ans;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:32:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27