oj.uz

Submission #46173

# Submission time Handle Problem Language Result Execution time Memory
46173 2018-04-17T11:46:49 Z Extazy Palindromes (APIO14_palindrome) C++17
73 / 100
 710 ms 56864 KB 
#include <bits/stdc++.h>
#define endl '\n'
 
using namespace std;
 
const unsigned long long B1 = 131, B2 = 137, MOD = (1e9) + 7;
const int N = 300007;
const int P = 24000;
struct rolling_hash {
    unsigned long long h1;
    unsigned h2;
    
    rolling_hash(): h1(0), h2(0) {}
 
    void append(char a) {
        h1*=B1;
        h1+=a-'a'+1;
        h2=(h2*1llu*B2+a-'a'+1)%MOD;
    }
 
    bool operator ==(const rolling_hash &a) const {
        return h1==a.h1 && h2==a.h2;
    }
 
    bool operator <(const rolling_hash &a) const {
        return h1==a.h1 ? h2<a.h2 : h1<a.h1;
    }
};
 
struct hash_rolling_hash {
    unsigned long long operator () (const rolling_hash &a) const {
        return a.h1^(a.h2<<30);
    }
};
 
struct item {
    rolling_hash hash;
    int from,to;
 
    item(){}
    item(rolling_hash a, int b, int c): hash(a), from(b), to(c) {}
    
    bool operator <(const item &a) const {
        return to-from+1==a.to-a.from+1 ? hash<a.hash : to-from+1<a.to-a.from+1;
    }
};
 
int n;
char a[N];
unsigned long long pw1[N];
unsigned pw2[N];
rolling_hash ph[N],sh[N];
unordered_map < rolling_hash, pair < int, int >, hash_rolling_hash > interval;
unordered_map < rolling_hash, int, hash_rolling_hash > current_cnt;
priority_queue < item > q;
long long ans;
list < item > wait[N];
 
inline rolling_hash get_prefix_hash(rolling_hash *a, int l, int r) {
    rolling_hash hl=a[l-1],hr=a[r];
 
    hl.h1*=pw1[r-l+1];
    hl.h2=hl.h2*1llu*pw2[r-l+1]%MOD;
 
    hr.h1-=hl.h1;
    hr.h2-=hl.h2;
    hr.h2+=MOD;
    hr.h2%=MOD;
    
    return hr;
}
 
inline rolling_hash get_suffix_hash(rolling_hash *a, int l, int r) {
    rolling_hash hl=a[l],hr=a[r+1];
    
    hr.h1*=pw1[r-l+1];
    hr.h2=hr.h2*1llu*pw2[r-l+1]%MOD;
 
    hl.h1-=hr.h1;
    hl.h2-=hr.h2;
    hl.h2+=MOD;
    hl.h2%=MOD;
 
    return hl;
}
 
inline bool is_palindrome(int l, int r) {
    return get_prefix_hash(ph,l,r)==get_suffix_hash(sh,l,r);
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int i,j;
    rolling_hash h;
 
    pw1[0]=pw2[0]=1;
    for(i=1;i<N;i++) {
        pw1[i]=pw1[i-1]*B1;
        pw2[i]=pw2[i-1]*1llu*B2%MOD;
    }
 
    while((a[++n]=getchar_unlocked())!='\n');
    --n;
 
    h=rolling_hash();
    for(i=1;i<=n;i++) {
        h.append(a[i]);
        ph[i]=h;
    }
 
    h=rolling_hash();
    for(i=n;i>=1;i--) {
        h.append(a[i]);
        sh[i]=h;
    }
 
    for(i=1;i<=n;i++) {
        int left=0,right=min(i,n-i+1),middle;
 
        while(right-left>1) {
            middle=(left+right)/2;
            
            if(is_palindrome(i-middle,i+middle)) left=middle;
            else right=middle;
        }

		int to = (n>100000 ? P : 0);
        for(j=left;j>=to;j--) {
            h=get_prefix_hash(ph,i-j,i+j);
 
            if(interval.find(h)!=interval.end()) break;
            
            wait[2*j+1].push_back(item(h,i-j,i+j));
            interval[h]=make_pair(i-j,i+j);
        }
 
        h=get_prefix_hash(ph,i-left,i+left);
        ++current_cnt[h];
    }
 
    for(i=1;i<n;i++) if(a[i]==a[i+1]) {
        int left=0,right=min(i,n-i),middle;
        
        while(right-left>1) {
            middle=(left+right)/2;
 
            if(is_palindrome(i-middle,i+1+middle)) left=middle;
            else right=middle;
        }

        if(n>100000 && left<10000) continue;
 
      	int to = (n>100000 ? P : 0);
        for(j=left;j>=to;j--) {
            h=get_prefix_hash(ph,i-j,i+1+j);
 
            if(interval.find(h)!=interval.end()) break;
            
            wait[2*j+2].push_back(item(h,i-j,i+1+j));
            interval[h]=make_pair(i-j,i+1+j);
        }
 
        h=get_prefix_hash(ph,i-left,i+1+left);
        ++current_cnt[h];
    }

    for(i=n;i>2;i--) {
        for(item curr: wait[i]) {
            int cnt=current_cnt[curr.hash];
            long long curr_ans=cnt*1ll*i;
            current_cnt.erase(curr.hash);
 
            if(curr_ans>ans) {
                ans=curr_ans;
            }
 
            curr.hash=get_prefix_hash(ph,curr.from+1,curr.to-1);
            pair < int, int > seg=interval[curr.hash];
            curr.from=seg.first;
            curr.to=seg.second;
            current_cnt[curr.hash]+=cnt;
        }
    }
 
    for(;i>=1;i--) {
        for(item curr: wait[i]) { 
            int cnt=current_cnt[curr.hash];
            long long curr_ans=cnt*1ll*i;
 
            if(curr_ans>ans) {
                ans=curr_ans;
            }
        }
    }
 
    printf("%lld\n", ans);
    
    return 0;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 20216 KB Output is correct
2 Correct 22 ms 20324 KB Output is correct
3 Correct 21 ms 20488 KB Output is correct
4 Correct 22 ms 20488 KB Output is correct
5 Correct 18 ms 20488 KB Output is correct
6 Correct 18 ms 20516 KB Output is correct
7 Correct 22 ms 20692 KB Output is correct
8 Correct 17 ms 20704 KB Output is correct
9 Correct 22 ms 20704 KB Output is correct
10 Correct 17 ms 20704 KB Output is correct
11 Correct 18 ms 20716 KB Output is correct
12 Correct 17 ms 20716 KB Output is correct
13 Correct 22 ms 20716 KB Output is correct
14 Correct 22 ms 20716 KB Output is correct
15 Correct 22 ms 20716 KB Output is correct
16 Correct 19 ms 20716 KB Output is correct
17 Correct 22 ms 20716 KB Output is correct
18 Correct 19 ms 20716 KB Output is correct
19 Correct 22 ms 20716 KB Output is correct
20 Correct 21 ms 20716 KB Output is correct
21 Correct 18 ms 20716 KB Output is correct
22 Correct 17 ms 20716 KB Output is correct
23 Correct 18 ms 20716 KB Output is correct
24 Correct 18 ms 20716 KB Output is correct
25 Correct 20 ms 20716 KB Output is correct
26 Correct 17 ms 20716 KB Output is correct
27 Correct 21 ms 20716 KB Output is correct
28 Correct 22 ms 20716 KB Output is correct
29 Correct 18 ms 20716 KB Output is correct
30 Correct 18 ms 20716 KB Output is correct
31 Correct 18 ms 20716 KB Output is correct
32 Correct 19 ms 20716 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 20732 KB Output is correct
2 Correct 19 ms 20732 KB Output is correct
3 Correct 19 ms 20732 KB Output is correct
4 Correct 19 ms 20784 KB Output is correct
5 Correct 19 ms 20784 KB Output is correct
6 Correct 20 ms 20784 KB Output is correct
7 Correct 19 ms 20784 KB Output is correct
8 Correct 19 ms 20784 KB Output is correct
9 Correct 20 ms 20784 KB Output is correct
10 Correct 20 ms 20784 KB Output is correct
11 Correct 19 ms 20784 KB Output is correct
12 Correct 20 ms 20784 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 22140 KB Output is correct
2 Correct 28 ms 22140 KB Output is correct
3 Correct 30 ms 22144 KB Output is correct
4 Correct 31 ms 22144 KB Output is correct
5 Correct 28 ms 22144 KB Output is correct
6 Correct 28 ms 22144 KB Output is correct
7 Correct 30 ms 22144 KB Output is correct
8 Correct 22 ms 22144 KB Output is correct
9 Correct 22 ms 22144 KB Output is correct
10 Correct 26 ms 22144 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 408 ms 36564 KB Output is correct
2 Correct 240 ms 36564 KB Output is correct
3 Correct 270 ms 36564 KB Output is correct
4 Correct 273 ms 36632 KB Output is correct
5 Correct 175 ms 36632 KB Output is correct
6 Correct 165 ms 36632 KB Output is correct
7 Correct 248 ms 36632 KB Output is correct
8 Correct 51 ms 36632 KB Output is correct
9 Correct 94 ms 36632 KB Output is correct
10 Correct 150 ms 36632 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 710 ms 56864 KB Output is correct
2 Incorrect 358 ms 56864 KB Output isn't correct
3 Halted 0 ms 0 KB -