#include <cstdio>
#include <cassert>
#include <cstring>
#include <utility>
#include <algorithm>
#define let const auto
#define rep(name,beg,end) for(auto lim_##name = end,name = beg;name <= lim_##name;name++)
#define per(name,beg,end) for(auto lim_##name = end,name = beg;name >= lim_##name;name--)
#define repn(lim) for(auto REPN_lIM = lim,REPN = 1;REPN <= REPN_lIM;REPN++)
#define debug(...) fprintf(stderr,__VA_ARGS__)
#define trace() debug("line : %d, Function : %s\n",__LINE__,__FUNCTION__)
using ll = long long;
constexpr int maxn = 1e5 +10;
constexpr int lowbit(const int x){return x & (-x);}
int n;
char buf[maxn];
template <int base,int mod>
struct Hash{
static int add(const int a,const int b){return a + b >= mod ? a + b - mod : a + b;}
static int sub(const int a,const int b){return a >= b ? a - b : a - b + mod;}
static int mul(const int a,const int b){return 1ll * a * b % mod;}
int pw[maxn],sum[maxn],sum_rev[maxn];
void init(){
pw[0] = 1;
rep(i,1,n)pw[i] = mul(pw[i - 1],base);
rep(i,1,n)sum[i] = add(mul(sum[i - 1],base),buf[i]);
per(i,n,1)sum_rev[i] = add(mul(sum_rev[i + 1],base),buf[i]);
}
int query(const int l,const int r){
return sub(sum[r],mul(sum[l - 1],pw[r - l + 1]));
}
int query_rev(const int l,const int r){
return sub(sum_rev[l],mul(sum_rev[r + 1],pw[r - l + 1]));
}
};
Hash<127,1000000000 + 7> ha;
Hash<131,1000000000 + 9> hb;
struct fenwick{
ll f[maxn];
void add(int pos,const ll v){
while(pos <= n + 1){
f[pos] += v;
pos += lowbit(pos);
}
}
ll query(int pos){
ll res = 0;
while(pos){
res += f[pos];
pos -= lowbit(pos);
}
return res;
}
}fs,fsi;
ll delta[maxn][26];
void modify(const int l,const int r,const int beg,const int delta){
if(l > r)return;
fs.add(l,beg);
fs.add(l + 1,delta - beg);
fs.add(r + 1,-(r - l + 1) * delta - beg);
fs.add(r + 2,(r - l) * delta + beg);
fsi.add(l,1ll * l * beg);
fsi.add(l + 1,1ll * (l + 1) * (delta - beg));
fsi.add(r + 1,1ll * (r + 1) * (-(r - l + 1) * delta - beg));
fsi.add(r + 2,1ll * (r + 2) * ((r - l) * delta + beg));
}
ll query(const int p){
return 1ll * (p + 1) * fs.query(p) - fsi.query(p);
}
ll sum,mx;
int main(){
// std::freopen("palinilap.in","r",stdin);
// std::freopen("palinilap.out","w",stdout);
std::scanf("%s",buf + 1);
n = std::strlen(buf + 1);
ha.init(); hb.init();
rep(i,1,n){
int l = 0,r = std::min(i - 1,n - i),ans = 0;
while(l <= r){
let mid = (l + r) >> 1;
if(std::make_pair(ha.query_rev(i - mid,i),hb.query_rev(i - mid,i)) == std::make_pair(ha.query(i,i + mid),hb.query(i,i + mid)))ans = mid,l = mid + 1;
else r = mid - 1;
}
sum += ans + 1;
rep(c,0,25)
if(c != buf[i] - 'a')
delta[i][c] += ans + 1;
modify(i - ans,i,1,1);
modify(i + 1,i + ans,ans,-1);
if(i - ans != 1 && i + ans != n){
let t = ans;
l = 0,r = std::min(i - t - 3,n - (i + t + 2)),ans = -1;
while(l <= r){
let mid = (l + r) >> 1;
if(std::make_pair(ha.query_rev(i - t - 2 - mid,i - t - 2),hb.query_rev(i - t - 2 - mid,i - t - 2)) == std::make_pair(ha.query(i + t + 2,i + t + 2 + mid),hb.query(i + t + 2,i + t + 2 + mid)))ans = mid,l = mid + 1;
else r = mid - 1;
}
delta[i - t - 1][buf[i + t + 1] - 'a'] += ans + 2;
delta[i + t + 1][buf[i - t - 1] - 'a'] += ans + 2;
}
}
rep(i,1,n - 1){
if(buf[i] != buf[i + 1]){
int l = 0,r = std::min(i - 2,n - i - 2),ans = -1;
while(l <= r){
let mid = (l + r) >> 1;
if(std::make_pair(ha.query_rev(i - 1 - mid,i - 1),hb.query_rev(i - 1 - mid,i - 1)) == std::make_pair(ha.query(i + 2,i + 2 + mid),hb.query(i + 2,i + 2 + mid)))ans = mid,l = mid + 1;
else r = mid - 1;
}
delta[i][buf[i + 1] - 'a'] += ans + 2;
delta[i + 1][buf[i] - 'a'] += ans + 2;
continue;
}
int l = 0,r = std::min(i - 1,n - i - 1),ans = 0;
while(l <= r){
let mid = (l + r) >> 1;
if(std::make_pair(ha.query_rev(i - mid,i),hb.query_rev(i - mid,i)) == std::make_pair(ha.query(i + 1,i + 1 + mid),hb.query(i + 1,i + 1 + mid)))ans = mid,l = mid + 1;
else r = mid - 1;
}
sum += ans + 1;
modify(i - ans,i,1,1);
modify(i + 1,i + 1 + ans,ans + 1,-1);
if(i - ans != 1 && i + 1 + ans != n){
let t = ans;
l = 0,r = std::min(i - ans - 3,n - (i + ans + 3)),ans = -1;
while(l <= r){
let mid = (l + r) >> 1;
if(std::make_pair(ha.query_rev(i - t - 2 - mid,i - t - 2),hb.query_rev(i - t - 2 - mid,i - t - 2)) == std::make_pair(ha.query(i + t + 3,i + t + 3 + mid),hb.query(i + t + 3,i + t + 3 + mid)))ans = mid,l = mid + 1;
else r = mid - 1;
}
delta[i - t - 1][buf[i + t + 2] - 'a'] += ans + 2;
delta[i + t + 2][buf[i - t - 1] - 'a'] += ans + 2;
}
}
rep(i,1,n)
rep(c,0,25)
if(c != buf[i] - 'a')
mx = std::max(mx,delta[i][c] - query(i));
std::printf("%lld\n",sum + mx);
std::fclose(stdin);
std::fclose(stdout);
return 0;
}
Compilation message
palinilap.cpp: In function 'int main()':
palinilap.cpp:80:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
80 | std::scanf("%s",buf + 1);
| ~~~~~~~~~~^~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
0 ms |
332 KB |
Output is correct |
| 2 |
Correct |
0 ms |
332 KB |
Output is correct |
| 3 |
Correct |
0 ms |
332 KB |
Output is correct |
| 4 |
Correct |
0 ms |
332 KB |
Output is correct |
| 5 |
Correct |
1 ms |
332 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
1484 KB |
Output is correct |
| 2 |
Correct |
5 ms |
1460 KB |
Output is correct |
| 3 |
Correct |
7 ms |
1480 KB |
Output is correct |
| 4 |
Correct |
5 ms |
1044 KB |
Output is correct |
| 5 |
Correct |
5 ms |
1228 KB |
Output is correct |
| 6 |
Correct |
7 ms |
1460 KB |
Output is correct |
| 7 |
Correct |
6 ms |
1484 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
147 ms |
24616 KB |
Output is correct |
| 2 |
Correct |
134 ms |
24532 KB |
Output is correct |
| 3 |
Correct |
147 ms |
24620 KB |
Output is correct |
| 4 |
Correct |
140 ms |
24516 KB |
Output is correct |
| 5 |
Correct |
140 ms |
24672 KB |
Output is correct |
| 6 |
Correct |
129 ms |
24600 KB |
Output is correct |
| 7 |
Correct |
129 ms |
24616 KB |
Output is correct |
| 8 |
Correct |
125 ms |
24536 KB |
Output is correct |
| 9 |
Correct |
131 ms |
24516 KB |
Output is correct |
| 10 |
Correct |
133 ms |
24616 KB |
Output is correct |
| 11 |
Correct |
136 ms |
24660 KB |
Output is correct |
| 12 |
Correct |
164 ms |
24512 KB |
Output is correct |
| 13 |
Correct |
137 ms |
24620 KB |
Output is correct |
| 14 |
Correct |
145 ms |
24628 KB |
Output is correct |
| 15 |
Correct |
134 ms |
24588 KB |
Output is correct |
| 16 |
Correct |
157 ms |
24616 KB |
Output is correct |
| 17 |
Correct |
110 ms |
24548 KB |
Output is correct |
| 18 |
Correct |
132 ms |
24620 KB |
Output is correct |
| 19 |
Correct |
109 ms |
24616 KB |
Output is correct |
