oj.uz

Submission #46182

# Submission time Handle Problem Language Result Execution time Memory
46182 2018-04-17T12:24:05 Z Extazy Palindromes (APIO14_palindrome) C++17
47 / 100
 751 ms 54344 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;
 
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 {
    unsigned long long hash;
    int from,to;
 
    item(){}
    item(unsigned long long 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 < unsigned long long, pair < int, int > > interval;
unordered_map < unsigned long long, int > 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;
    }
#define h1 h2 
    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;
        }
 
        for(j=left;j>=0;j--) {
            h=get_prefix_hash(ph,i-j,i+j);
 
            if(interval.find(h.h1)!=interval.end()) break;
            
            wait[2*j+1].push_back(item(h.h1,i-j,i+j));
            interval[h.h1]=make_pair(i-j,i+j);
        }
 
        h=get_prefix_hash(ph,i-left,i+left);
        ++current_cnt[h.h1];
    }
 
    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;
        }
 
        for(j=left;j>=0;j--) {
            h=get_prefix_hash(ph,i-j,i+1+j);
 
            if(interval.find(h.h1)!=interval.end()) break;
            
            wait[2*j+2].push_back(item(h.h1,i-j,i+1+j));
            interval[h.h1]=make_pair(i-j,i+1+j);
        }
 
        h=get_prefix_hash(ph,i-left,i+1+left);
        ++current_cnt[h.h1];
    }
 
    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).h1;
            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 20344 KB Output is correct
2 Correct 18 ms 20344 KB Output is correct
3 Correct 22 ms 20396 KB Output is correct
4 Correct 18 ms 20396 KB Output is correct
5 Correct 18 ms 20448 KB Output is correct
6 Correct 17 ms 20480 KB Output is correct
7 Correct 17 ms 20480 KB Output is correct
8 Correct 17 ms 20480 KB Output is correct
9 Correct 17 ms 20584 KB Output is correct
10 Correct 18 ms 20584 KB Output is correct
11 Correct 17 ms 20584 KB Output is correct
12 Correct 17 ms 20584 KB Output is correct
13 Correct 17 ms 20584 KB Output is correct
14 Correct 17 ms 20584 KB Output is correct
15 Correct 17 ms 20584 KB Output is correct
16 Correct 19 ms 20584 KB Output is correct
17 Correct 20 ms 20584 KB Output is correct
18 Correct 17 ms 20584 KB Output is correct
19 Correct 17 ms 20584 KB Output is correct
20 Correct 17 ms 20584 KB Output is correct
21 Correct 18 ms 20584 KB Output is correct
22 Correct 18 ms 20584 KB Output is correct
23 Correct 17 ms 20584 KB Output is correct
24 Correct 18 ms 20584 KB Output is correct
25 Correct 17 ms 20584 KB Output is correct
26 Correct 18 ms 20608 KB Output is correct
27 Correct 18 ms 20608 KB Output is correct
28 Correct 18 ms 20692 KB Output is correct
29 Correct 18 ms 20712 KB Output is correct
30 Correct 18 ms 20712 KB Output is correct
31 Correct 19 ms 20712 KB Output is correct
32 Correct 18 ms 20712 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 20716 KB Output is correct
2 Correct 24 ms 20716 KB Output is correct
3 Correct 19 ms 20716 KB Output is correct
4 Correct 24 ms 20716 KB Output is correct
5 Correct 19 ms 20716 KB Output is correct
6 Correct 24 ms 20716 KB Output is correct
7 Correct 20 ms 20716 KB Output is correct
8 Correct 18 ms 20844 KB Output is correct
9 Correct 19 ms 20844 KB Output is correct
10 Correct 19 ms 20844 KB Output is correct
11 Correct 18 ms 20844 KB Output is correct
12 Correct 19 ms 20844 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 21884 KB Output is correct
2 Correct 27 ms 21884 KB Output is correct
3 Correct 35 ms 21904 KB Output is correct
4 Correct 38 ms 21904 KB Output is correct
5 Correct 27 ms 21904 KB Output is correct
6 Correct 33 ms 21904 KB Output is correct
7 Correct 36 ms 21904 KB Output is correct
8 Correct 20 ms 21904 KB Output is correct
9 Correct 21 ms 21904 KB Output is correct
10 Correct 24 ms 21904 KB Output is correct

Subtask #4
0 / 26.0

# Verdict Execution time Memory Grader output
1 Incorrect 238 ms 33472 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 751 ms 54344 KB Output isn't correct
2 Halted 0 ms 0 KB -