29 lines
725 B
C++
29 lines
725 B
C++
template <typename T>
|
|
vector<int> manacher(const vector<T>& s, const T& never) {
|
|
vector<T> t = { never };
|
|
for (auto&& c : s) {
|
|
t.emplace_back(c);
|
|
t.emplace_back(never);
|
|
}
|
|
int n = t.size();
|
|
vector<int> r(n);
|
|
for (int i = 0, j = 0; i < n; ++i) {
|
|
if (2 * j - i >= 0 && j + r[j] > i) {
|
|
r[i] = min(r[2 * j - i], j + r[j] - i);
|
|
}
|
|
while (i - r[i] >= 0 && i + r[i] < n && t[i - r[i]] == t[i + r[i]]) {
|
|
r[i] += 1;
|
|
}
|
|
if (i + r[i] > j + r[j]) {
|
|
j = i;
|
|
}
|
|
}
|
|
for (int i = 0; i < n; i += 2) {
|
|
r[i] = (r[i] - 1) / 2;
|
|
}
|
|
for (int i = 1; i < n; i += 2) {
|
|
r[i] /= 2;
|
|
}
|
|
return r;
|
|
}
|