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Submission #230816

# Submission time Handle Problem Language Result Execution time Memory
230816 2020-05-11T21:13:52 Z alishahali1382 Palindromes (APIO14_palindrome) C++14
47 / 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];
int seg[MAXN<<2];
vector<pii> vec[MAXN<<1], Q[MAXN<<1];
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)));
}*/

void Maximize(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]=max(seg[id], val);
		return ;
	}
	int mid=(tl+tr)>>1;
	Maximize(id<<1, tl, mid, l, r, val);
	Maximize(id<<1 | 1, mid, tr, l, r, val);
}

int Get(int id, int tl, int tr, int pos){
	if (pos<tl || tr<=pos) return seg[0];
	if (tr-tl==1) return seg[id];
	int mid=(tl+tr)>>1;
	return max(seg[id], max(Get(id<<1, tl, mid, pos), Get(id<<1 | 1, mid, tr, pos)));
}

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);
		ans=max(ans, 2ll*len);
		vec[2*i+1].pb({i+1-len, i+1});
		//Add(1, 0, n, i+1-len, i+1, 2*i+1);
	}
	for (int i=0; i<n; i++){
		int len=GetLcp(i, 2*n-i);
		ans=max(ans, 2*len-1ll);
		vec[2*i].pb({i-len+1, i+1});
		//Add(1, 0, n, i-len+1, i+1, 2*i);
	}
	//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];//, debug(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 ;
		Q[2*P[i]+lcp[i]].pb({P[i], ted});
		//cerr<<"query: "<<P[i]<<' '<<2*P[i]+lcp[i]<<' '<<ted<<'\n';
		//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]))
	}
	memset(seg, -1, sizeof(seg));
	for (int i=0; i<2*n; i++){
		for (pii p:Q[i]){
			ans=max(ans, (Get(1, 0, n, p.first)-2*p.first+1ll)*p.second);
			/*
			if (ans==4){
				debug(Get(1, 0, n, p.first))
				cerr<<"Get "<<p.first<<' '<<p.second<<' '<<i<<endl;
				return 0;
			}*/
		}
		for (pii p:vec[i]) Maximize(1, 0, n, p.first, p.second, i);
	}
	cout<<ans<<'\n';
	
	return 0;
}
/*
abaa

*/

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 33280 KB Output is correct
2 Correct 23 ms 33280 KB Output is correct
3 Correct 23 ms 33280 KB Output is correct
4 Correct 23 ms 33280 KB Output is correct
5 Correct 23 ms 33280 KB Output is correct
6 Correct 24 ms 33280 KB Output is correct
7 Correct 23 ms 33152 KB Output is correct
8 Correct 23 ms 33280 KB Output is correct
9 Correct 23 ms 33280 KB Output is correct
10 Correct 24 ms 33280 KB Output is correct
11 Correct 24 ms 33272 KB Output is correct
12 Correct 23 ms 33272 KB Output is correct
13 Correct 24 ms 33280 KB Output is correct
14 Correct 23 ms 33280 KB Output is correct
15 Correct 23 ms 33280 KB Output is correct
16 Correct 23 ms 33272 KB Output is correct
17 Correct 24 ms 33280 KB Output is correct
18 Correct 24 ms 33280 KB Output is correct
19 Correct 24 ms 33272 KB Output is correct
20 Correct 23 ms 33280 KB Output is correct
21 Correct 24 ms 33280 KB Output is correct
22 Correct 24 ms 33280 KB Output is correct
23 Correct 23 ms 33280 KB Output is correct
24 Correct 24 ms 33280 KB Output is correct
25 Correct 24 ms 33280 KB Output is correct
26 Correct 26 ms 33280 KB Output is correct
27 Correct 23 ms 33280 KB Output is correct
28 Correct 24 ms 33280 KB Output is correct
29 Correct 23 ms 33280 KB Output is correct
30 Correct 24 ms 33280 KB Output is correct
31 Correct 24 ms 33280 KB Output is correct
32 Correct 24 ms 33280 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 33536 KB Output is correct
2 Correct 26 ms 33536 KB Output is correct
3 Correct 27 ms 33536 KB Output is correct
4 Correct 25 ms 33528 KB Output is correct
5 Correct 27 ms 33536 KB Output is correct
6 Correct 26 ms 33536 KB Output is correct
7 Correct 26 ms 33536 KB Output is correct
8 Correct 26 ms 33536 KB Output is correct
9 Correct 26 ms 33528 KB Output is correct
10 Correct 26 ms 33536 KB Output is correct
11 Correct 26 ms 33536 KB Output is correct
12 Correct 25 ms 33536 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 60 ms 36088 KB Output is correct
2 Correct 59 ms 35960 KB Output is correct
3 Correct 60 ms 35960 KB Output is correct
4 Correct 60 ms 36088 KB Output is correct
5 Correct 62 ms 36088 KB Output is correct
6 Correct 61 ms 36088 KB Output is correct
7 Correct 62 ms 36092 KB Output is correct
8 Correct 60 ms 35960 KB Output is correct
9 Correct 60 ms 36088 KB Output is correct
10 Correct 62 ms 35964 KB Output is correct

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 829 ms 61252 KB Output is correct
2 Correct 718 ms 61248 KB Output is correct
3 Correct 729 ms 61312 KB Output is correct
4 Correct 639 ms 61312 KB Output is correct
5 Execution timed out 1046 ms 61240 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 -