Submission #551787

#	Time	Username	Problem	Language	Result	Execution time	Memory
551787		MarcoMeijer	Palindromes (APIO14_palindrome)	C++14	100 / 100	25 ms	35328 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
 
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e18
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
 
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
 
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const vector<T>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class T> void OUT(const vector<T>& x) {RE(i,x.size()) OUT(i==0?"":" ",x[i]);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
 
//===================//
//  Added libraries  //
//===================//
 
//===================//
//end added libraries//
//===================//
 
void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}
 
 
//===================//
//   begin program   //
//===================//
 
const int MX = 3e5+4;
 
int n;
 
struct Node {
    int nxt[26], sufflink, len;
    int cnt=1;
} tree[MX];
 
string s;
int suf, num;
 
void initTree() {
    num = suf = 2;
    tree[1].len = -1; tree[1].sufflink = 1;
    tree[2].len =  0; tree[2].sufflink = 1;
}
void addLetter(int pos) {
    int cur = suf, curLen = 0;
 
    while(1) {
        curLen = tree[cur].len;
        if(pos-1-curLen >= 0 && s[pos-1-curLen] == s[pos])
            break;
        cur = tree[cur].sufflink;
    }
    if(tree[cur].nxt[s[pos]]) {
        suf = tree[cur].nxt[s[pos]];
        tree[suf].cnt++;
        return;
    }
 
    suf = ++num;
    tree[num].len = tree[cur].len+2;
    tree[cur].nxt[s[pos]] = suf;
 
    if(tree[num].len == 1) {
        tree[num].sufflink = 2;
        return;
    }
 
    while(1) {
        cur = tree[cur].sufflink;
        curLen = tree[cur].len;
        if(pos-1-curLen >= 0 && s[pos-1-curLen] == s[pos]) {
            tree[num].sufflink = tree[cur].nxt[s[pos]];
            break;
        }
    }
}
 
void program() {
    IN(s); n=s.sz;
    FOR(i,s) i-='a';
    initTree();
    RE(i,n) addLetter(i);
    ll ans=0;
    REV(u,1,num+1) {
        tree[tree[u].sufflink].cnt += tree[u].cnt;
        ans = max(ans, (ll)tree[u].cnt*(ll)tree[u].len);
    }
    OUTL(ans);
}

Compilation message (stderr)

palindrome.cpp: In function 'void addLetter(int)':
palindrome.cpp:93:28: warning: array subscript has type 'char' [-Wchar-subscripts]
   93 |     if(tree[cur].nxt[s[pos]]) {
      |                            ^
palindrome.cpp:94:35: warning: array subscript has type 'char' [-Wchar-subscripts]
   94 |         suf = tree[cur].nxt[s[pos]];
      |                                   ^
palindrome.cpp:101:25: warning: array subscript has type 'char' [-Wchar-subscripts]
  101 |     tree[cur].nxt[s[pos]] = suf;
      |                         ^
palindrome.cpp:112:54: warning: array subscript has type 'char' [-Wchar-subscripts]
  112 |             tree[num].sufflink = tree[cur].nxt[s[pos]];
      |                                                      ^

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 27 / 27