// cre: Nguyen Hoang Hung - Train VOI 2024
#include <bits/stdc++.h>
#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
#define EACH(it,a) for(__typeof(a.begin()) it = a.begin(); it != a.end(); ++it)
#define debug(x) { cerr << #x << " = "; cerr << (x) << endl; }
#define PR(a,n) { cerr << #a << " = "; FOR(_,1,n) cerr << a[_] << ' '; cerr << endl; }
#define PR0(a,n) { cerr << #a << " = "; REP(_,n) cerr << a[_] << ' '; cerr << endl; }
#define bit(X, i) ((X >> i) & 1)
#define cntbit(X) __builtin_popcountll(X)
#define fi first
#define se second
#define pb push_back
#define all(X) begin(X), end(X)
#define SZ(X) ((int)(X).size())
#define RR(X) X.resize(unique(all(X)) - begin(X))
#define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
using namespace std;
template <typename T>
bool maximize(T &x, T y)
{
if(x < y)
x = y;
else
return 0;
return 1;
}
template <typename T>
bool minimize(T &x, T y)
{
if(x > y)
x = y;
else
return 0;
return 1;
}
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
ll Rand(ll l, ll r) { return l + rand() % (r - l + 1); }
const int maxN = 1e6;
const ll inf = 1e18+7;
const int MOD = 1e9 + 7;
const double PI = acos(-1);
const int base = 31;
/*
-------------------------------------------------------------------------------------
END OF TEMPLATE
-------------------------------------------------------------------------------------
Nguyen Hoang Hung - catlover
Training for VOI24 gold medal
-------------------------------------------------------------------------------------
*/
string S;
int N;
int Hash[maxN+5], rHash[maxN+5];
int pw[maxN+5];
void in()
{
cin >> S;
N = SZ(S);
}
int getHash(int l, int r, int H[maxN+5])
{
return (H[r] - H[l - 1] * pw[r - l + 1] + 1ll * MOD * MOD) % MOD;
}
bool check_palin(int i, int j)
{
int tmp1 = getHash(i, j, Hash);
int tmp2 = getHash(N - j + 1, N - i + 1, rHash);
return tmp1 == tmp2;
}
void init()
{
string tmp = S;
S = ' ' + S;
reverse(all(tmp));
tmp = ' ' + tmp;
pw[0] = 1;
Hash[0] = 0;
rHash[0] = 0;
FOR(i, 1, N)
{
Hash[i] = (Hash[i - 1] * base + S[i] - 'a') % MOD;
rHash[i] = (rHash[i - 1] * base + tmp[i] - 'a') % MOD;
pw[i] = pw[i - 1] * base % MOD;
}
}
int calc()
{
int res = 0;
FOR(i, 1, N)
{
FOR(j, i, N)
{
if(check_palin(i, j)) ++res;
}
}
return res;
}
void trau()
{
string o = S;
int ans = 0;
FOR(i, 0, N - 1)
{
FOR(j, 0, 25)
{
S = o;
S[i] = char(j + 'a');
init();
maximize(ans, calc());
}
}
cout << ans;
}
void solve() {
in();
trau();
}
void solve_TestCase() {
int testcase; cin >> testcase;
while(testcase --> 0)
{
solve();
}
}
int main() {
ios::sync_with_stdio(0); cin.tie(0);
file("PALIVAL");
// solve_TestCase();
solve();
cerr << "\nTime : " << clock()/1000.0 << "s\n";
return 0;
}
Compilation message
palinilap.cpp: In function 'int main()':
palinilap.cpp:22:57: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
22 | #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palinilap.cpp:156:5: note: in expansion of macro 'file'
156 | file("PALIVAL");
| ^~~~
palinilap.cpp:22:90: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
22 | #define file(name) if (fopen(name".inp", "r")) { freopen(name".inp", "r", stdin); freopen(name".out", "w", stdout); }
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
palinilap.cpp:156:5: note: in expansion of macro 'file'
156 | file("PALIVAL");
| ^~~~
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
22 ms |
4440 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
1070 ms |
4444 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Execution timed out |
1024 ms |
9048 KB |
Time limit exceeded |
2 |
Halted |
0 ms |
0 KB |
- |