oj.uz

Submission #230806

# Submission time Handle Problem Language Result Execution time Memory
230806 2020-05-11T20:27:45 Z alishahali1382 Palindromes (APIO14_palindrome) C++14
47 / 100
 1000 ms 81020 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
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 28544 KB Output is correct
2 Correct 23 ms 28544 KB Output is correct
3 Correct 22 ms 28544 KB Output is correct
4 Correct 22 ms 28544 KB Output is correct
5 Correct 22 ms 28544 KB Output is correct
6 Correct 22 ms 28544 KB Output is correct
7 Correct 22 ms 28544 KB Output is correct
8 Correct 23 ms 28544 KB Output is correct
9 Correct 21 ms 28544 KB Output is correct
10 Correct 22 ms 28544 KB Output is correct
11 Correct 21 ms 28544 KB Output is correct
12 Correct 22 ms 28544 KB Output is correct
13 Correct 22 ms 28544 KB Output is correct
14 Correct 25 ms 28544 KB Output is correct
15 Correct 22 ms 28544 KB Output is correct
16 Correct 22 ms 28544 KB Output is correct
17 Correct 22 ms 28544 KB Output is correct
18 Correct 23 ms 28520 KB Output is correct
19 Correct 23 ms 28544 KB Output is correct
20 Correct 22 ms 28544 KB Output is correct
21 Correct 21 ms 28544 KB Output is correct
22 Correct 30 ms 28544 KB Output is correct
23 Correct 28 ms 28544 KB Output is correct
24 Correct 21 ms 28544 KB Output is correct
25 Correct 22 ms 28544 KB Output is correct
26 Correct 22 ms 28544 KB Output is correct
27 Correct 21 ms 28544 KB Output is correct
28 Correct 30 ms 28544 KB Output is correct
29 Correct 22 ms 28544 KB Output is correct
30 Correct 23 ms 28544 KB Output is correct
31 Correct 26 ms 28544 KB Output is correct
32 Correct 26 ms 28544 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 28800 KB Output is correct
2 Correct 31 ms 28800 KB Output is correct
3 Correct 40 ms 28800 KB Output is correct
4 Correct 26 ms 28800 KB Output is correct
5 Correct 26 ms 28800 KB Output is correct
6 Correct 28 ms 28800 KB Output is correct
7 Correct 25 ms 28704 KB Output is correct
8 Correct 25 ms 28792 KB Output is correct
9 Correct 25 ms 28792 KB Output is correct
10 Correct 25 ms 28800 KB Output is correct
11 Correct 25 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 70 ms 31352 KB Output is correct
2 Correct 63 ms 31352 KB Output is correct
3 Correct 75 ms 31864 KB Output is correct
4 Correct 74 ms 31992 KB Output is correct
5 Correct 62 ms 30840 KB Output is correct
6 Correct 61 ms 30968 KB Output is correct
7 Correct 60 ms 31328 KB Output is correct
8 Correct 66 ms 30688 KB Output is correct
9 Correct 60 ms 30712 KB Output is correct
10 Correct 71 ms 30968 KB Output is correct

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 879 ms 56552 KB Output is correct
2 Correct 817 ms 56960 KB Output is correct
3 Correct 919 ms 62332 KB Output is correct
4 Correct 854 ms 62952 KB Output is correct
5 Execution timed out 1024 ms 51200 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 1073 ms 81020 KB Time limit exceeded
2 Halted 0 ms 0 KB -