oj.uz

Submission #364306

# Submission time Handle Problem Language Result Execution time Memory
364306 2021-02-08T20:58:36 Z ACmachine Palindromes (APIO14_palindrome) C++17
100 / 100
 83 ms 61068 KB 
#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;
typedef double db;
typedef string str;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pii> vpii;
typedef vector<pll> vpll;
typedef vector<str> vstr;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back 
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define rsz resize 
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)
	
const double EPS = 1e-9;
const int MOD = 1e9+7; // 998244353;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

#ifdef DEBUG
#define DBG if(1)
#else
#define DBG if(0)
#endif

#define dbg(x) cout << "(" << #x << " : " << x << ")" << endl;
// ostreams
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}
// istreams
template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }
template<class T, class U>
istream& operator>>(istream& in, pair<T, U> &p){ in >> p.ff >> p.ss; return in; }
//searches
template<typename T, typename U>
T bsl(T lo, T hi, U f){ hi++; T mid; while(lo < hi){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid+1; } return lo; }
template<typename U>
double bsld(double lo, double hi, U f, double p = 1e-9){ int r = 3 + (int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? hi = mid : lo = mid; } return (lo + hi)/2; }
template<typename T, typename U>
T bsh(T lo, T hi, U f){ lo--; T mid; while(lo < hi){ mid = (lo + hi + 1)/2; f(mid) ? lo = mid : hi = mid-1; } return lo; }
template<typename U>
double bshd(double lo, double hi, U f, double p = 1e-9){ int r = 3+(int)log2((hi - lo)/p); double mid; while(r--){ mid = (lo + hi)/2; f(mid) ? lo = mid : hi = mid; } return (lo + hi)/2; }
// some more utility functions
template<typename T>
pair<T, int> get_min(vector<T> &v){ typename vector<T> :: iterator it = min_element(v.begin(), v.end()); return mp(*it, it - v.begin());}
template<typename T>
pair<T, int> get_max(vector<T> &v){ typename vector<T> :: iterator it = max_element(v.begin(), v.end()); return mp(*it, it - v.begin());}        
template<typename T> bool ckmin(T& a, const T& b){return b < a ? a = b , true : false;}
template<typename T> bool ckmax(T& a, const T& b){return b > a ? a = b, true : false;}

const int K = 26;
struct node{
    array<int, K> next;
    int len;
    int fail; 
    int lazy = 0;
    node(){
        fill(all(next), -1);
    }
};
struct paltree{
    vector<node> tree;
    string s; 
    int max_suffix_palindrome;
    paltree(string _s) : s(_s){
        tree.resize(2);
        tree[0].len = -1; tree[0].fail = 0;
        tree[1].len = 0; tree[1].fail = 0;
        max_suffix_palindrome = 1;
    }
    void addletter(int pos){
        int curr = max_suffix_palindrome;
        int currlen = 0;
        while(true){
            currlen = tree[curr].len;
            if(pos - 1 - currlen >= 0 && s[pos - 1 - currlen] == s[pos])
                break;
            curr = tree[curr].fail;
        }
        if(tree[curr].next[s[pos] - 'a'] != -1){
            max_suffix_palindrome = tree[curr].next[s[pos] - 'a'];
            tree[max_suffix_palindrome].lazy++;
            return;
        }
        tree.push_back(node());
        tree.back().len = tree[curr].len + 2;
        tree[curr].next[s[pos] - 'a'] = (int)tree.size() - 1;
        int nw = (int)tree.size() - 1;
        max_suffix_palindrome = nw;
        tree[max_suffix_palindrome].lazy++;
        if(tree[nw].len == 1){
            tree[nw].fail = 1;
            return;
        }
        while(true){
            curr = tree[curr].fail;
            currlen = tree[curr].len;
            if(pos - 1 - currlen >= 0 && s[pos - 1 - currlen] == s[pos]){
                tree[nw].fail = tree[curr].next[s[pos] - 'a'];
                break;
            }
        }
    }
    void construct_paltree(){
        REP(i, s.length()){
            addletter(i);
        }
    }
    void propagate_lazy(){
        vi dist(tree.size(), -1);
        queue<int> q;
        q.push(0);
        q.push(1);
        dist[0] = dist[1] = 0;
        stack<int> st;
        st.push(0); st.push(1);
        while(!q.empty()){
            int v = q.front();
            q.pop();
            REP(i, K){
                if(tree[v].next[i] != -1){
                    if(dist[tree[v].next[i]] == -1){
                        q.push(tree[v].next[i]);
                        dist[tree[v].next[i]] = dist[v] + 1;
                        st.push(tree[v].next[i]);
                    }
                }
            }
        }
        while(!st.empty()){
            int v = st.top();
            st.pop();
            tree[tree[v].fail].lazy += tree[v].lazy;
        }
    }
};
    
int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
	string s; cin >> s;
    paltree P(s); 
    P.construct_paltree();
    P.propagate_lazy();
    ll ans = 0;
    REP(j, P.tree.size()){
        ans = max(ans, (ll)P.tree[j].len * P.tree[j].lazy);
    }
    cout << ans << "\n";
	
    return 0;
}

Compilation message

palindrome.cpp: In member function 'void paltree::construct_paltree()':
palindrome.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
palindrome.cpp:28:18: note: in expansion of macro 'FOR'
   28 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
palindrome.cpp:138:9: note: in expansion of macro 'REP'
  138 |         REP(i, s.length()){
      |         ^~~
palindrome.cpp: In function 'int main()':
palindrome.cpp:26:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<node>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
palindrome.cpp:28:18: note: in expansion of macro 'FOR'
   28 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
palindrome.cpp:179:5: note: in expansion of macro 'REP'
  179 |     REP(j, P.tree.size()){
      |     ^~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 0 ms 364 KB Output is correct
4 Correct 0 ms 364 KB Output is correct
5 Correct 0 ms 364 KB Output is correct
6 Correct 0 ms 364 KB Output is correct
7 Correct 0 ms 364 KB Output is correct
8 Correct 0 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 0 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 364 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 512 KB Output is correct
29 Correct 1 ms 364 KB Output is correct
30 Correct 1 ms 364 KB Output is correct
31 Correct 1 ms 364 KB Output is correct
32 Correct 1 ms 364 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 620 KB Output is correct
2 Correct 1 ms 620 KB Output is correct
3 Correct 1 ms 620 KB Output is correct
4 Correct 1 ms 620 KB Output is correct
5 Correct 1 ms 620 KB Output is correct
6 Correct 1 ms 620 KB Output is correct
7 Correct 1 ms 620 KB Output is correct
8 Correct 1 ms 620 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 1 ms 364 KB Output is correct
12 Correct 1 ms 492 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 2388 KB Output is correct
2 Correct 3 ms 2388 KB Output is correct
3 Correct 3 ms 2388 KB Output is correct
4 Correct 3 ms 2388 KB Output is correct
5 Correct 3 ms 2388 KB Output is correct
6 Correct 3 ms 2388 KB Output is correct
7 Correct 3 ms 2412 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 2 ms 1468 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 15632 KB Output is correct
2 Correct 26 ms 15760 KB Output is correct
3 Correct 28 ms 15632 KB Output is correct
4 Correct 24 ms 15760 KB Output is correct
5 Correct 24 ms 15760 KB Output is correct
6 Correct 20 ms 15760 KB Output is correct
7 Correct 23 ms 15760 KB Output is correct
8 Correct 3 ms 876 KB Output is correct
9 Correct 7 ms 4568 KB Output is correct
10 Correct 22 ms 15760 KB Output is correct

Subtask #5
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 82 ms 60572 KB Output is correct
2 Correct 82 ms 60544 KB Output is correct
3 Correct 78 ms 60692 KB Output is correct
4 Correct 80 ms 60928 KB Output is correct
5 Correct 82 ms 61068 KB Output is correct
6 Correct 78 ms 60928 KB Output is correct
7 Correct 61 ms 31616 KB Output is correct
8 Correct 7 ms 1672 KB Output is correct
9 Correct 7 ms 1652 KB Output is correct
10 Correct 57 ms 31288 KB Output is correct
11 Correct 83 ms 60948 KB Output is correct
12 Correct 15 ms 5124 KB Output is correct