oj.uz

Submission #230803

# Submission time Handle Problem Language Result Execution time Memory
230803 2020-05-11T20:23:14 Z alishahali1382 Palindromes (APIO14_palindrome) C++14
39 / 100
 1000 ms 80896 KB 
#include <bits/stdc++.h>
#pragma GCC optimize ("O2")
#pragma GCC optimize ("unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
 
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;
 
const ld eps=1e-7;
const int inf=1000000010;
const ll INF=10000000000000010LL;
const int mod=1000000007;
const int MAXN=300010, LOG=21;
 
int n, m, k, u, v, x, y, t, a, b;
ll ans;
int Rank[MAXN<<1][LOG], P[MAXN<<1], pw;
int lcp[MAXN], L[MAXN], R[MAXN];
vector<int> seg[MAXN<<2];
string S;
 
inline bool cmp(int x, int y){
	if (Rank[x][pw-1]!=Rank[y][pw-1]) return Rank[x][pw-1]<Rank[y][pw-1];
	if (max(x, y)+(1<<(pw-1))>=m) return x>y;
	return Rank[x+(1<<(pw-1))][pw-1]<Rank[y+(1<<(pw-1))][pw-1];
}
 
void BuildSuffixArray(){
	for (int i=0; i<m; i++) Rank[i][0]=S[i], P[i]=i;
	for (pw=1; pw<LOG; pw++){
		sort(P, P+m, cmp);
		Rank[P[0]][pw]=0;
		for (int i=1; i<m; i++) Rank[P[i]][pw]=Rank[P[i-1]][pw] + cmp(P[i-1], P[i]);
	}
}
 
int GetLcp(int x, int y){
	if (x>y) swap(x, y);
	int res=0;
	for (int i=LOG-1; ~i; i--) if (y<m && Rank[x][i]==Rank[y][i]){
		x+=(1<<i);
		y+=(1<<i);
		res|=(1<<i);
	}
	return res;
}
 
void Add(int id, int tl, int tr, int l, int r, int val){
	if (r<=tl || tr<=l) return ;
	if (l<=tl && tr<=r){
		seg[id].pb(val);
		return ;
	}
	int mid=(tl+tr)>>1;
	Add(id<<1, tl, mid, l, r, val);
	Add(id<<1 | 1, mid, tr, l, r, val);
}
 
int GetPalindrome(int id, int tl, int tr, int pos, int val){
	if (pos<tl || tr<=pos) return 0;
	int res=0;
	if (seg[id].size() && seg[id][0]<val) res=(*--lower_bound(all(seg[id]), val))-2*pos+1;
	if (tr-tl==1) return res;
	int mid=(tl+tr)>>1;
	return max(res, max(GetPalindrome(id<<1, tl, mid, pos, val), GetPalindrome(id<<1 | 1, mid, tr, pos, val)));
}
 
int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>S;
	n=S.size();
	S+="#";
	for (int i=n-1; ~i; i--) S+=S[i];
	m=S.size();
	BuildSuffixArray();
	/*
	debug(S)
	debug(GetLcp(0, 2*n))
	for (int i=0; i<m; i++) cerr<<P[i]<<" \n"[i==m-1];
	*/
	
	for (int i=0; i<n; i++){
		int len=GetLcp(i+1, 2*n-i);
		Add(1, 0, n, i+1-len, i+1, 2*i+1);
		ans=max(ans, 2ll*len);
	}
	for (int i=0; i<n; i++){
		int len=GetLcp(i, 2*n-i);
		Add(1, 0, n, i-len+1, i+1, 2*i);
		ans=max(ans, 2*len-1ll);
	}
	for (int i=0; i<4*MAXN; i++) sort(all(seg[i]));
	
	int ted=0;
	for (int i=0; i<m; i++) if (P[i]<n) P[ted++]=P[i];
	
	for (int i=0; i+1<n; i++) lcp[i]=GetLcp(P[i], P[i+1]);
	for (int i=0; i+1<n; i++) for (L[i]=i-1; ~L[i] && lcp[L[i]]>=lcp[i]; L[i]=L[L[i]]);
	for (int i=n-2; i; i--) for (R[i]=i+1; R[i]<n-1 && lcp[R[i]]>=lcp[i]; R[i]=R[R[i]]);
	for (int i=0; i<=n-2; i++){
		ll ted=(R[i]-L[i]);
		if (!ted) continue ;
		ans=max(ans, GetPalindrome(1, 0, n, P[i], 2*P[i]+lcp[i])*ted);
		//debug2(P[i], GetPalindrome(1, 0, n, P[i], 2*P[i]+lcp[i]))
	}
	cout<<ans<<'\n';
	
	return 0;
}

Subtask #1
0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 28544 KB Output is correct
2 Correct 22 ms 28576 KB Output is correct
3 Correct 22 ms 28544 KB Output is correct
4 Runtime error 80 ms 57592 KB Execution killed with signal 11 (could be triggered by violating memory limits)
5 Halted 0 ms 0 KB -

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 28800 KB Output is correct
2 Correct 24 ms 28800 KB Output is correct
3 Correct 25 ms 28800 KB Output is correct
4 Correct 24 ms 28800 KB Output is correct
5 Correct 25 ms 28928 KB Output is correct
6 Correct 25 ms 28800 KB Output is correct
7 Correct 25 ms 28800 KB Output is correct
8 Correct 26 ms 28800 KB Output is correct
9 Correct 25 ms 28800 KB Output is correct
10 Correct 25 ms 28800 KB Output is correct
11 Correct 24 ms 28800 KB Output is correct
12 Correct 25 ms 28800 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 64 ms 31352 KB Output is correct
2 Correct 62 ms 31352 KB Output is correct
3 Correct 68 ms 31992 KB Output is correct
4 Correct 69 ms 31864 KB Output is correct
5 Correct 61 ms 30840 KB Output is correct
6 Correct 60 ms 30968 KB Output is correct
7 Correct 60 ms 31352 KB Output is correct
8 Correct 58 ms 30712 KB Output is correct
9 Correct 58 ms 30712 KB Output is correct
10 Correct 61 ms 30840 KB Output is correct

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 867 ms 56432 KB Output is correct
2 Correct 780 ms 56832 KB Output is correct
3 Correct 860 ms 62200 KB Output is correct
4 Correct 799 ms 62720 KB Output is correct
5 Execution timed out 1018 ms 51076 KB Time limit exceeded
6 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1097 ms 80896 KB Time limit exceeded
2 Halted 0 ms 0 KB -