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Submission #168097

# Submission time Handle Problem Language Result Execution time Memory
168097 2019-12-11T11:06:27 Z HungAnhGoldIBO2020 Palindromes (APIO14_palindrome) C++14
47 / 100
 616 ms 102264 KB 
/*
abacaba
*/
#include<bits/stdc++.h>
#define int long long
#define hash hash1
using namespace std;
const int N=3e5+4;
const int mod=2000002183;
const int base=211;
int hash[N],rev_hash[N],mul[N],max1=1,sum[N];
map<int,int> cnt;
bool used[N];
int gethash(int l,int r){
	return ((hash[r]-hash[l-1]*mul[r-l+1])%mod+mod)%mod;
}
int gethash_rev(int l,int r){
	return ((rev_hash[l]-rev_hash[r+1]*mul[r-l+1])%mod+mod)%mod;
}
struct node{
	int nxt[26],len,suf;
};
node Eer[N];
int sz=0,lst;
string s;
void add(int idx){
//	cout<<idx<<" BEGIN"<<endl;
	int cha=(s[idx]-'a');
	while(idx-Eer[lst].len-1<0||s[idx]!=s[idx-Eer[lst].len-1]){
		lst=Eer[lst].suf;
	}
	if(!Eer[lst].nxt[cha]){
		sz++;
		Eer[lst].nxt[cha]=sz;
		Eer[sz].len=Eer[lst].len+2;
		if(Eer[sz].len!=1){
			int sf=Eer[lst].suf;
			while(idx-Eer[sf].len-1<0||s[idx]!=s[idx-Eer[sf].len-1]){
				sf=Eer[sf].suf;
			}
			Eer[sz].suf=Eer[sf].nxt[cha];
		}
		else{
			Eer[sz].suf=2;
		}
	}
	lst=Eer[lst].nxt[cha];
	return;
}
void build(string s1){
	sz=2;
	Eer[1].len=-1;
	Eer[1].suf=0;
	Eer[2].len=0;
	Eer[2].suf=1;
	lst=2;
	s=s1;
	for(int i=0;i<s.size();i++){
		add(i);
	}
}
void dfs(int x,int val){
	assert(!used[x]);
	used[x]=true;
	sum[x]=cnt[val];
	for(int i=0;i<26;i++){
		if(Eer[x].nxt[i]){
			if(x==1){
				dfs(Eer[x].nxt[i],i+1);
			}
			else{
				dfs(Eer[x].nxt[i],(i+1 + val*base + (i+1)*mul[Eer[x].len+1])%mod);
			}
			sum[x]+=sum[Eer[x].nxt[i]];
		}
	}
	max1=max(max1,Eer[x].len * sum[x]);
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	string s1;
	cin>>s1;
	build(s1);
	int n=s1.size(),i,j,k,l;
	s1=" "+s1;
	mul[0]=1;
	for(i=1;i<=n;i++){
		hash[i]=(hash[i-1]*base+(s1[i]-'a'+1))%mod;
		mul[i]=(mul[i-1]*base)%mod;
	}
	for(i=n;i>0;i--){
		rev_hash[i]=(rev_hash[i+1]*base+(s1[i]-'a'+1))%mod;
	}
	for(i=1;i<=n;i++){
		k=0;
		l=min(i-1,n-i);
		while(k<l){
			j=(k+l+1)>>1;
			if(gethash(i-j,i+j)==gethash_rev(i-j,i+j)){
				k=j;
			}
			else{
				l=j-1;
			}
		}
		cnt[gethash(i-k,i+k)]++;
		if(i<=n&&s1[i]==s1[i+1]){
			k=0;
			l=min(i-1,n-i-1);
			while(k<l){
				j=(k+l+1)>>1;
				if(gethash(i-j,i+1+j)==gethash_rev(i-j,i+1+j)){
					k=j;
				}
				else{
					l=j-1;
				}
			}
			cnt[gethash(i-k,i+1+k)]++;
		}
	}
	dfs(1,0);
	dfs(2,0);
	cout<<max1;
}

Compilation message

palindrome.cpp: In function 'void build(std::__cxx11::string)':
palindrome.cpp:58:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.size();i++){
              ~^~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 380 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 380 KB Output is correct
6 Correct 2 ms 376 KB Output is correct
7 Correct 2 ms 348 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 376 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 376 KB Output is correct
13 Correct 2 ms 376 KB Output is correct
14 Correct 2 ms 376 KB Output is correct
15 Correct 2 ms 376 KB Output is correct
16 Correct 2 ms 376 KB Output is correct
17 Correct 2 ms 376 KB Output is correct
18 Correct 2 ms 376 KB Output is correct
19 Correct 2 ms 376 KB Output is correct
20 Correct 2 ms 376 KB Output is correct
21 Correct 2 ms 376 KB Output is correct
22 Correct 2 ms 376 KB Output is correct
23 Correct 2 ms 376 KB Output is correct
24 Correct 2 ms 376 KB Output is correct
25 Correct 2 ms 376 KB Output is correct
26 Correct 2 ms 376 KB Output is correct
27 Correct 2 ms 504 KB Output is correct
28 Correct 2 ms 376 KB Output is correct
29 Correct 2 ms 376 KB Output is correct
30 Correct 2 ms 376 KB Output is correct
31 Correct 2 ms 380 KB Output is correct
32 Correct 2 ms 376 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 760 KB Output is correct
2 Correct 3 ms 760 KB Output is correct
3 Correct 3 ms 760 KB Output is correct
4 Correct 3 ms 680 KB Output is correct
5 Correct 3 ms 760 KB Output is correct
6 Correct 3 ms 760 KB Output is correct
7 Correct 3 ms 760 KB Output is correct
8 Correct 3 ms 764 KB Output is correct
9 Correct 3 ms 632 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 632 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 3704 KB Output is correct
2 Correct 11 ms 3704 KB Output is correct
3 Correct 13 ms 3800 KB Output is correct
4 Correct 14 ms 3704 KB Output is correct
5 Correct 9 ms 3704 KB Output is correct
6 Correct 10 ms 3704 KB Output is correct
7 Correct 12 ms 3576 KB Output is correct
8 Correct 4 ms 760 KB Output is correct
9 Correct 4 ms 760 KB Output is correct
10 Correct 7 ms 2680 KB Output is correct

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Incorrect 153 ms 34424 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 616 ms 102264 KB Output isn't correct
2 Halted 0 ms 0 KB -