Submission #172456

#	Time	Username	Problem	Language	Result	Execution time	Memory
172456		dndhk	Palindromes (APIO14_palindrome)	C++14	23 / 100	708 ms	131076 KiB

palindrome

#include <bits/stdc++.h>

#define all(v) (v).begin(), (v).end()
#define sortv(v) sort(all(v))
#define uniqv(v) (v).erase(unique(all(v)), (v).end())
#define pb push_back
#define FI first
#define SE second
#define lb lower_bound
#define ub upper_bound
#define mp make_pair
#define test 1
#define TEST if(test)

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;

const int MOD = 1000000007; // 998244353
const int INF = 2e9;
const ll INFLL = 1e18;
const ll p = 29;
const ll P1 = 1000000007;
const ll P2 = 1000000009;
const int MAX_N = 300000;

int N;
string str;
vector<pll> vt[MAX_N+1];

ll ans = 0;

int main(){
	cin>>str;
	N = str.size();
	for(int i=0; i<N; i++){
		pll now = {str[i]-'a'+1, str[i]-'a'+1};
		ll m1=p, m2=p;
		pll now2 = {str[i]-'a'+1, str[i]-'a'+1};
		vt[1].pb(now);
		for(int j=i+1; j<N; j++){
			now.first = (now.first * p + str[j]-'a' + 1) % P1;
			now.second = (now.second * p + str[j]-'a'+1) % P2;
			now2.first = (now2.first + m1 * (ll)(str[j]-'a'+1)) % P1;
			now2.second = (now2.second + m2 * (ll)(str[j]-'a'+1)) % P2;
			m1 = (m1 * p) % P1; m2 = (m2 * p) % P2;
			if(now.first==now2.first && now.second==now2.second)	vt[j-i+1].pb(now);
		}
	}
	for(int i=1; i<=N; i++){
		sort(vt[i].begin(), vt[i].end());
		int s = 0, e = 0;
		while(s<vt[i].size()){
			while(e<vt[i].size()-1 && vt[i][s].first==vt[i][e+1].first && vt[i][s].second==vt[i][e+1].second){
				e++;
			}
			ans = max(ans, (ll)(e-s+1) * (ll)i);
			s = e+1; e++;
		}
	}
	cout<<ans;
	return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:56:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(s<vt[i].size()){
         ~^~~~~~~~~~~~~
palindrome.cpp:57:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(e<vt[i].size()-1 && vt[i][s].first==vt[i][e+1].first && vt[i][s].second==vt[i][e+1].second){
          ~^~~~~~~~~~~~~~~

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