Submission #887388

#	Time	Username	Problem	Language	Result	Execution time	Memory
887388		Kutan	Palindromes (APIO14_palindrome)	C++14	23 / 100	120 ms	131072 KiB

palindrome

// Cao Quang Hung
#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <cwchar>
#include <cwctype>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>

using namespace std;
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int,int>
#define pll pair<long long , long long>
#define vi vector<int>
#define vpii vector<pii>
#define SZ(x) ((int)(x.size()))
#define fi first
#define se second
#define IN(x,y) ((y).find((x))!=(y).end())
#define ALL(t) t.begin(),t.end()
#define FOREACH(i,t) for (typeof(t.begin()) i=t.begin(); i!=t.end(); i++)
#define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
#define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
#define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define dem(x) __builtin_popcount(x)
#define Mask(x) (1LL << (x))
#define BIT(x, i) ((x) >> (i) & 1)
#define ln '\n'
#define io_faster ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
///mt19937 rnd(time(0));

const int INF = 1e9 , mod = 1e9 + 7;

template <class T1, class T2>
inline T1 mul(T1& x, const T2 &k){ return x = (1LL * x * k) % mod; }

template <class T1 , class T2>
inline T1 pw(T1 x, T2 k){T1 res = 1; for (; k ; k >>= 1){ if (k & 1) mul(res, x); mul(x, x); } return res;}

template <class T>
inline bool minimize(T &x, const T &y){ if (x > y){x = y; return 1;} return 0; }

template <class T>
inline bool maximize(T &x, const T &y){ if (x < y){x = y; return 1;} return 0; }

template <class T>
inline void add(T &x , const T &y){ if ((x += y) >= mod) x -= mod; }

template <class T>
inline T product (const T &x , const T &y) { return 1LL * x * y % mod; }

#define PROB "a"
void file(){
    if(fopen(PROB".inp", "r")){
        freopen(PROB".inp","r",stdin);
        freopen(PROB".out","w",stdout);
    }
}
void sinh_(){
//    srand(time(0));
//    freopen(PROB".inp" , "w" , stdout);
//    int n;
}

typedef long long ll;
typedef double db;
const int N = 3e5 + 5;

string s;
int n;

void readip(){
    cin >> s;
    n = SZ(s);
    s = ' ' + s;
}

namespace sub1 {
    vector<int> Hashup, Hashdown, Pow;
    const int base = 9907;


    int gethashup(int l, int r) {
        return (Hashup[r] + 1LL * mod * mod - 1LL * Hashup[l - 1] * Pow[r - l + 1]) % mod;
    }

    int gethashdown(int l, int r) {
        return (Hashdown[l] + 1LL * mod * mod - 1LL * Hashdown[r + 1] * Pow[r - l + 1]) % mod;
    }


    void solve() {
        Hashup.assign(n + 2, 0);
        Hashdown.assign(n + 2, 0);
        Pow.assign(n + 2, 0);
        Pow[0] = 1;
        REP(i, 1, n) Pow[i] = product(Pow[i - 1], base);

        Hashup[0] = 0;
        REP(i, 1, n) Hashup[i] = (1LL * Hashup[i - 1] * base + s[i] - 'a' + 1) % mod;
        Hashdown[n + 1] = 0;
        REPD(i, n, 1) Hashdown[i] = (1LL * Hashdown[i + 1] * base + s[i] - 'a' + 1) % mod;

        vpii v;
        REP(i, 1, n) REP(j, i, n) { 
            int hashlef = gethashup(i, j);
            if (gethashdown(i, j) == hashlef) 
                v.eb(hashlef, j - i + 1);
        }
        sort(ALL(v));
        ll res = 0;
        FOR(i, v.size()) {
            int j = i;
            while(j < v.size() && v[i] == v[j]) ++j; --j;
            maximize(res, 1LL * (j - i + 1) * v[i].second);
            i = j;
        }
        cout << res << ln;
    }       
};

void solve(){   
    if (n <= 1e4) {
        sub1::solve();
        return;
    }
}

int main(){
    sinh_();
    io_faster
    file();
    int t = 1;
//    cin >> t;
    while (t--){
        readip();
        solve();
    }
}

Compilation message (stderr)

palindrome.cpp: In function 'void sub1::solve()':
palindrome.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
palindrome.cpp:167:9: note: in expansion of macro 'REP'
  167 |         REP(i, 1, n) Pow[i] = product(Pow[i - 1], base);
      |         ^~~
palindrome.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
palindrome.cpp:170:9: note: in expansion of macro 'REP'
  170 |         REP(i, 1, n) Hashup[i] = (1LL * Hashup[i - 1] * base + s[i] - 'a' + 1) % mod;
      |         ^~~
palindrome.cpp:93:29: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   93 | #define REPD(i,a,b) for(int (i)=(a); (i)>=(b);--i)
      |                             ^
palindrome.cpp:172:9: note: in expansion of macro 'REPD'
  172 |         REPD(i, n, 1) Hashdown[i] = (1LL * Hashdown[i + 1] * base + s[i] - 'a' + 1) % mod;
      |         ^~~~
palindrome.cpp:92:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
palindrome.cpp:175:9: note: in expansion of macro 'REP'
  175 |         REP(i, 1, n) REP(j, i, n) {
      |         ^~~
palindrome.cpp:92:28: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   92 | #define REP(i,a,b) for(int (i)=(a);(i)<=(b);++i)
      |                            ^
palindrome.cpp:175:22: note: in expansion of macro 'REP'
  175 |         REP(i, 1, n) REP(j, i, n) {
      |                      ^~~
palindrome.cpp:94:28: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   94 | #define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
      |                            ^
palindrome.cpp:182:9: note: in expansion of macro 'FOR'
  182 |         FOR(i, v.size()) {
      |         ^~~
palindrome.cpp:94:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   94 | #define FOR(i, n) for (int (i) = 0; (i) < (n); ++(i))
      |                                     ~~~~^~~~~
palindrome.cpp:182:9: note: in expansion of macro 'FOR'
  182 |         FOR(i, v.size()) {
      |         ^~~
palindrome.cpp:184:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  184 |             while(j < v.size() && v[i] == v[j]) ++j; --j;
      |                   ~~^~~~~~~~~~
palindrome.cpp:184:13: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
  184 |             while(j < v.size() && v[i] == v[j]) ++j; --j;
      |             ^~~~~
palindrome.cpp:184:54: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
  184 |             while(j < v.size() && v[i] == v[j]) ++j; --j;
      |                                                      ^~
palindrome.cpp: In function 'void file()':
palindrome.cpp:125:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  125 |         freopen(PROB".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:126:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  126 |         freopen(PROB".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27