#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <bits/stdc++.h>
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef pair<ldb,ldb> pdd;
#define ff(i,a,b) for(int i = a; i <= b; i++)
#define fb(i,b,a) for(int i = b; i >= a; i--)
#define trav(a,x) for(auto& a : x)
#define sz(a) (int)(a).size()
#define fi first
#define se second
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
template<typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
// os.order_of_key(k) the number of elements in the os less than k
// *os.find_by_order(k) print the k-th smallest number in os(0-based)
const int mod = 1000000007;
const int inf = 1e9 + 5;
const int mxN = 200005;
int n;
string s;
int d1[mxN];
int d2[mxN];
void manacher(string a){
int N = sz(a);
int L = 0, R = -1;
ff(i,0,N - 1){
int j = (i > R ? 1 : min(d1[L + R - i], R - i + 1));
while(i >= j && i + j < N && a[i - j] == a[i + j])j += 1;
d1[i] = j--;
if(i + j > R){
L = i - j;
R = i + j;
}
}
L = 0, R = -1;
ff(i,0,N - 1){
int j = (i > R ? 0 : min(d2[L + R - i + 1], R - i + 1));
while(i > j && i + j < N && a[i - j - 1] == a[i + j])j += 1;
d2[i] = j--;
if(i + j > R){
L = i - j - 1;
R = i + j;
}
}
}
int main(){
cin.tie(0)->sync_with_stdio(0);
cin >> s; n = sz(s);
manacher(s);
int uk = 0;
ff(i,0,n - 1)uk += d1[i] + d2[i];
int rez = uk;
ff(i,0,n - 1){
char old = s[i];
for(char a = 'a'; a <= 'z'; a++){
if(s[i] == old)continue;
s[i] = a;
// Neparno
int cur = uk;
ff(j,0,i - 1){
if(j + d1[j] - 1 >= i){
cur -= d1[j];
cur += i - j;
}
if(j + d1[j] - 1 == i - 1){
int l = 2 * j - i, r = i;
while(0 <= l && l < n && 0 <= r && r < n && l <= r && s[l] == s[r]){
l -= 1; r += 1;
cur += 1;
}
}
}
ff(j,i + 1,n - 1){
if(j - d1[j] + 1 <= i){
cur -= d1[j];
cur += j - i;
}
if(j - d1[j] + 1 == i + 1){
int l = i, r = 2 * j - i;
while(0 <= l && l < n && 0 <= r && r < n && l <= r && s[l] == s[r]){
l -= 1; r += 1;
cur += 1;
}
}
}
// Parno
cur -= d2[i];
ff(j,0,i - 1){
if(j + d2[j] - 1 >= i){
cur -= d2[j];
cur += i - j;
}
if(j + d2[j] - 1 == i - 1){
int l = 2 * j - i - 1, r = i;
while(0 <= l && l < n && 0 <= r && r < n && l <= r && s[l] == s[r]){
l -= 1; r += 1;
cur += 1;
}
}
}
ff(j,i + 1,n - 1){
if(j - d2[j] <= i){
cur -= d2[j];
cur += j - i - 1;
}
if(j - d2[j] == i + 1){
int l = i, r = 2 * j - i - 1;
while(0 <= l && l < n && 0 <= r && r < n && l <= r && s[l] == s[r]){
l -= 1; r += 1;
cur += 1;
}
}
}
rez = max(rez, cur);
}
s[i] = old;
}
cout << rez << '\n';
return 0;
}
/*
// probati bojenje sahovski
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
344 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
344 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
1372 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
