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답안 #230827

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
230827 2020-05-11T21:41:46 Z alishahali1382 회문 (APIO14_palindrome) C++14
47 / 100
 1000 ms 81024 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;
 
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

# 결과 실행 시간 메모리 Grader output
1 Correct 23 ms 33236 KB Output is correct
2 Correct 23 ms 33280 KB Output is correct
3 Correct 23 ms 33280 KB Output is correct
4 Correct 24 ms 33280 KB Output is correct
5 Correct 24 ms 33280 KB Output is correct
6 Correct 23 ms 33280 KB Output is correct
7 Correct 23 ms 33280 KB Output is correct
8 Correct 24 ms 33280 KB Output is correct
9 Correct 22 ms 33280 KB Output is correct
10 Correct 23 ms 33280 KB Output is correct
11 Correct 23 ms 33280 KB Output is correct
12 Correct 24 ms 33280 KB Output is correct
13 Correct 23 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 33280 KB Output is correct
17 Correct 23 ms 33280 KB Output is correct
18 Correct 26 ms 33408 KB Output is correct
19 Correct 23 ms 33280 KB Output is correct
20 Correct 24 ms 33408 KB Output is correct
21 Correct 23 ms 33280 KB Output is correct
22 Correct 23 ms 33280 KB Output is correct
23 Correct 23 ms 33280 KB Output is correct
24 Correct 23 ms 33280 KB Output is correct
25 Correct 25 ms 33280 KB Output is correct
26 Correct 23 ms 33236 KB Output is correct
27 Correct 23 ms 33312 KB Output is correct
28 Correct 23 ms 33280 KB Output is correct
29 Correct 23 ms 33280 KB Output is correct
30 Correct 25 ms 33280 KB Output is correct
31 Correct 23 ms 33280 KB Output is correct
32 Correct 23 ms 33280 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 26 ms 33536 KB Output is correct
2 Correct 25 ms 33572 KB Output is correct
3 Correct 25 ms 33536 KB Output is correct
4 Correct 26 ms 33536 KB Output is correct
5 Correct 26 ms 33536 KB Output is correct
6 Correct 25 ms 33536 KB Output is correct
7 Correct 26 ms 33536 KB Output is correct
8 Correct 25 ms 33536 KB Output is correct
9 Correct 26 ms 33536 KB Output is correct
10 Correct 26 ms 33536 KB Output is correct
11 Correct 26 ms 33536 KB Output is correct
12 Correct 26 ms 33536 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 61 ms 36088 KB Output is correct
2 Correct 64 ms 36088 KB Output is correct
3 Correct 59 ms 36092 KB Output is correct
4 Correct 59 ms 36088 KB Output is correct
5 Correct 61 ms 36088 KB Output is correct
6 Correct 62 ms 36088 KB Output is correct
7 Correct 57 ms 36088 KB Output is correct
8 Correct 59 ms 36088 KB Output is correct
9 Correct 60 ms 36088 KB Output is correct
10 Correct 63 ms 36088 KB Output is correct

Subtask #4
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 816 ms 61440 KB Output is correct
2 Correct 726 ms 61312 KB Output is correct
3 Correct 725 ms 61440 KB Output is correct
4 Correct 647 ms 61440 KB Output is correct
5 Execution timed out 1053 ms 61440 KB Time limit exceeded
6 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 1098 ms 81024 KB Time limit exceeded
2 Halted 0 ms 0 KB -