#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 kol[mxN];
vector<int> L1[mxN];
vector<int> R1[mxN];
vector<int> L2[mxN];
vector<int> R2[mxN];
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];
ff(i,0,n - 1){
L1[i + d1[i] - 1].pb(i);
L2[i + d2[i] - 1].pb(i);
R1[i - d1[i] + 1].pb(i);
R2[i - d2[i]].pb(i);
kol[i] = uk;
}
ff(i,0,n - 1){
// LEVO
ff(j,0,i - 1){
if(j + d1[j] - 1 >= i){
kol[i] += i - (j + d1[j]);
}
}
ff(j,0,i){
if(j + d2[j] - 1 >= i){
kol[i] += i - (j + d2[j]);
}
}
}
fb(i,n - 1,0){
// DESNO
ff(j,i + 1,n - 1){
if(j - d1[j] + 1 <= i){
kol[i] += (j - d1[j]) - i;
}
}
ff(j,i + 1,n - 1){
if(j - d2[j] <= i){
kol[i] += (j - 1 - d2[j]) - i;
}
}
}
ff(i,0,n - 1){
char old = s[i]; int mx = 0;
for(char a = 'a'; a <= 'z'; a++){
if(old == a)continue;
s[i] = a; int cur = 0;
for(auto j : L1[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;
}
}
for(auto j : L2[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;
}
}
for(auto j : R1[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;
}
}
for(auto j : R2[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;
}
}
mx = max(mx, cur);
}
s[i] = old; kol[i] += mx;
}
int rez = uk;
ff(i,0,n - 1)rez = max(rez, kol[i]);
cout << rez << '\n';
return 0;
}
/*
// probati bojenje sahovski
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
8 ms |
19036 KB |
Output is correct |
| 2 |
Correct |
8 ms |
19036 KB |
Output is correct |
| 3 |
Correct |
8 ms |
19064 KB |
Output is correct |
| 4 |
Correct |
8 ms |
19036 KB |
Output is correct |
| 5 |
Correct |
8 ms |
19036 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
45 ms |
19696 KB |
Output is correct |
| 2 |
Correct |
58 ms |
19548 KB |
Output is correct |
| 3 |
Correct |
49 ms |
19804 KB |
Output is correct |
| 4 |
Correct |
23 ms |
19548 KB |
Output is correct |
| 5 |
Correct |
38 ms |
19548 KB |
Output is correct |
| 6 |
Correct |
48 ms |
19804 KB |
Output is correct |
| 7 |
Correct |
47 ms |
19804 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1065 ms |
29532 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
