/*
$$$$$$$\ $$\ $$$$$$$\
$$ __$$\ \__| $$ __$$\
$$ | $$ | $$$$$$\ $$$$$$\ $$\ $$$$$$$\ $$ | $$ | $$$$$$\ $$$$$$\ $$$$$$$\ $$$$$$\
$$$$$$$\ |$$ __$$\ $$ __$$\ $$ |$$ _____|$$$$$$$\ | \____$$\ $$ __$$\ $$ _____|\____$$\
$$ __$$\ $$ / $$ |$$ | \__|$$ |\$$$$$$\ $$ __$$\ $$$$$$$ |$$ | \__|$$ / $$$$$$$ |
$$ | $$ |$$ | $$ |$$ | $$ | \____$$\ $$ | $$ |$$ __$$ |$$ | $$ | $$ __$$ |
$$$$$$$ |\$$$$$$ |$$ | $$ |$$$$$$$ |$$$$$$$ |\$$$$$$$ |$$ | \$$$$$$$\\$$$$$$$ |
\_______/ \______/ \__| \__|\_______/ \_______/ \_______|\__| \_______|\_______|
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/detail/standard_policies.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define PB push_back
#define MP make_pair
#define INS insert
#define LB lower_bound
#define UB upper_bound
#define pii pair <int,int>
#define pll pair <long long, long long>
#define X first
#define Y second
#define _ << " " <<
#define sz(x) (int)x.size()
#define all(a) (a).begin(),(a).end()
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORD(i, a, b) for (int i = (a); i > (b); --i)
#define FORA(i, x) for (auto &i : x)
#define REP(i, n) FOR(i, 0, n)
#define BITS(x) __builtin_popcount(x)
#define SQ(a) (a) * (a)
#define TRACE(x) cout << #x " = " << (x) << '\n';
#define YES cout << "YES\n"
#define NO cout << "NO\n"
#define umap unordered_map
typedef long long ll;
typedef long double ld;
typedef vector <int> vi;
typedef vector <pii> vpi;
typedef vector <ll> vll;
typedef vector <pll> vpl;
typedef vector <double> vd;
typedef vector <ld> vld;
typedef vector<string> vs;
typedef tree<ll,null_type,less<ll>,rb_tree_tag,tree_order_statistics_node_update>ordered_set;
//find_by_order -> kti najmanji
//order_of_key -> koliko ima manjih od x
//((float) t)/CLOCKS_PER_SEC
const int MOD = 1e9 + 7;
const double PI = acos(-1);
const int INF = 1e9 + 10;
const ll INFL = 1e18 + 10;
const int ABC = 30;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int dox[] = {-1, 1, 0, 0, -1, -1, 1, 1};
const int doy[] = {0, 0, -1, 1, -1, 1, -1, 1};
inline int sum(int a, int b){
if (a + b < 0)
return (a + b + MOD) % MOD;
return (a + b) % MOD;
}
inline void add(int &a, int b){
a = sum(a, b);
}
inline int mul(ll a, ll b){
return ((a % MOD) * ((ll)b % MOD)) % MOD;
}
inline int sub(int a, int b){
return (a - b + MOD) % MOD;
}
inline int fast_pot(ll pot, ll n){
ll ret = 1;
while (n){
if (n & 1LL)
ret = (ret * pot) % MOD;
pot = (pot * pot) % MOD;
n >>= 1LL;
}
return ret;
}
inline int divide(int a, int b){
return mul(a, fast_pot(b, MOD - 2));
}
ll lcm(ll a, ll b){
return abs(a * b) / __gcd(a, b);
}
inline int ccw(pii a, pii b, pii c) {
return a.X * (b.Y - c.Y) + b.X * (c.Y - a.Y) + c.X * (a.Y - b.Y);
}
inline int CCW(pii A, pii B, pii C){
double val = ccw(A, B, C);
double eps = max(max(abs(A.X), abs(A.Y)), max(max(abs(B.X), abs(B.Y)), max(abs(C.X), abs(C.Y)))) / 1e9;
if (val <= -eps)
return -1;
if (val >= eps)
return 1;
return 0;
}
void to_upper(string &x){
REP(i, sz(x))
x[i] = toupper(x[i]);
}
void to_lower(string &x){
REP(i, sz(x))
x[i] = tolower(x[i]);
}
string its(ll x){
if (x == 0)
return "0";
string ret = "";
while (x > 0){
ret += (x % 10) + '0';
x /= 10;
}
reverse(all(ret));
return ret;
}
ll sti(string s){
ll ret = 0;
REP(i, sz(s)){
ret *= 10;
ret += (s[i] - '0');
}
return ret;
}
const int N = 1e5 + 10;
const int P = 31;
struct hsh{
int h[N], p[N], n;
void init(string s){
h[0] = s[0] - 'a' + 1;
p[0] = 1;
n = sz(s);
FOR(i, 1, n){
h[i] = sum(mul(h[i - 1], P), s[i] - 'a' + 1);
p[i] = mul(p[i - 1], P);
}
}
int get(int i, int l){
return sub(h[i + l - 1], (l ? mul(h[i - 1], p[l]) : 0));
}
} h, rh;
int n;
ll dp[N][30], l[N], r[N], cntL[N], cntR[N];
string s;
ll solve(){
int ret = 0;
ll sol = n;
FOR(i, 1, n - 1){
int lo = 0, hi;
if (s[i - 1] == s[i + 1]){
lo = 1, hi = min(i, n - i - 1);
while (lo < hi){
int mid = (lo + hi + 1) / 2;
//cout << mid _ s.substr(i - mid, mid) _ s.substr(i + 1, mid) _ h.get(i - mid, mid) _ rh.get(n - (i + mid) - 1, mid) << '\n';
if (h.get(i - mid, mid) == rh.get(n - (i + mid) - 1, mid))
lo = mid;
else
hi = mid - 1;
}
sol += lo;
l[i - 1] += lo;
if (i - lo - 1 >= 0)
cntL[i - lo - 1]--;
cntL[i - 1]++;
r[i + 1] += lo;
if (i + lo + 1 < n)
cntR[i + lo + 1]--;
cntR[i + 1]++;
}
lo++;
if (i - lo < 0 || i + lo >= n)
continue;
if (i - lo - 1 < 0 || i + lo + 1 >= n){
dp[i - lo][s[i + lo] - 'a']++;
dp[i + lo][s[i - lo] + 'a']++;
continue;
}
int l = i - lo - 1;
int r = i + lo + 1;
//cout << l _ r << '\n';
int lo1 = 0, hi1 = min(l, n - r - 1) + 1;
while (lo1 < hi1){
int mid = (lo1 + hi1 + 1) / 2;
if (h.get(l - mid + 1, mid) == rh.get(n - (r + mid - 1) - 1, mid))
lo1 = mid;
else
hi1 = mid - 1;
}
dp[l + 1][s[r - 1] - 'a'] += lo1 + 1;
dp[r - 1][s[l + 1] - 'a'] += lo1 + 1;
//cout << r - 1 _ lo1 + 1 << '\n';
}
FOR(i, 0, n - 1){
int lo = 0, hi;
if (s[i] == s[i + 1]){
lo = 1, hi = min(i + 1, n - i - 1);
while (lo < hi){
int mid = (lo + hi + 1) / 2;
if (h.get(i - mid + 1, mid) == rh.get(n - (i + mid) - 1, mid))
lo = mid;
else
hi = mid - 1;
}
sol += lo;
l[i] += lo;
cntL[i]++;
if (i - lo >= 0)
cntL[i - lo]--;
r[i + 1] += lo;
cntR[i + 1]++;
if (i + lo + 1 < n)
cntR[i + lo + 1]--;
}
lo++;
//cout << "lo" _ i _ lo << '\n';
if (i - lo + 1 < 0 || i + lo >= n)
continue;
if (i - lo < 0 || i + lo >= n){
dp[i - lo + 1][s[i + lo] - 'a']++;
dp[i + lo][s[i - lo + 1] - 'a']++;
continue;
}
int l = i - lo;
int r = i + lo + 1;
//cout << l _ r << '\n';
int lo1 = 0, hi1 = min(l, n - r - 1) + 1;
while (lo1 < hi1){
int mid = (lo1 + hi1 + 1) / 2;
if (h.get(l - mid + 1, mid) == rh.get(n - (r + mid - 1) - 1, mid))
lo1 = mid;
else
hi1 = mid - 1;
}
//cout << i _ lo1 << '\n';
dp[l + 1][s[r - 1] - 'a'] += lo1 + 1;
dp[r - 1][s[l + 1] - 'a'] += lo1 + 1;
//cout << r - 1 _ lo1 + 1 << '\n';
}
ll tmp = 0, dec = 0;
FORD(i, n - 1, -1){
tmp += l[i];
dec += cntL[i];
//cout << i _ -tmp << '\n';
REP(j, 26)
if (j != s[i] - 'a')
dp[i][j] -= tmp;
tmp -= dec;
}
tmp = 0, dec = 0;
REP(i, n){
tmp += r[i];
dec += cntR[i];
//dp[i] -= tmp;
//cout << i _ -tmp << '\n';
REP(j, 26)
if (j != s[i] - 'a')
dp[i][j] -= tmp;
tmp -= dec;
}
//cout << sol << '\n';
ll poc = sol;
REP(i, n){
REP(j, 26){
//cout << i _ j _ dp[i][j] _ poc + dp[i][j] << '\n';
sol = max(sol, poc + dp[i][j]);
}
}
return sol;
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> s;
n = sz(s);
h.init(s);
reverse(all(s));
rh.init(s);
reverse(all(s));
cout << solve() << '\n';
return 0;
}
Compilation message
palinilap.cpp: In function 'll solve()':
palinilap.cpp:176:6: warning: unused variable 'ret' [-Wunused-variable]
176 | int ret = 0;
| ^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
1 ms |
332 KB |
Output is correct |
| 2 |
Correct |
1 ms |
332 KB |
Output is correct |
| 3 |
Correct |
1 ms |
332 KB |
Output is correct |
| 4 |
Correct |
1 ms |
332 KB |
Output is correct |
| 5 |
Correct |
1 ms |
332 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
4 ms |
1740 KB |
Output is correct |
| 2 |
Correct |
4 ms |
1740 KB |
Output is correct |
| 3 |
Correct |
4 ms |
1736 KB |
Output is correct |
| 4 |
Correct |
3 ms |
1208 KB |
Output is correct |
| 5 |
Correct |
4 ms |
1484 KB |
Output is correct |
| 6 |
Correct |
5 ms |
1740 KB |
Output is correct |
| 7 |
Correct |
5 ms |
1740 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
132 ms |
28740 KB |
Output is correct |
| 2 |
Incorrect |
95 ms |
28596 KB |
Output isn't correct |
| 3 |
Halted |
0 ms |
0 KB |
- |
