bool home = 0;
bool verbose = 1;
#include <bits/stdc++.h>
using namespace std;
mt19937 rng(7777);
typedef double ld;
const ld PI = 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028410270193852110555964462294895493038196442881097566593344612847564823378678316527120190914;
using cd = complex<ld>;
int getlog2(int x) {
if (x == 1) return 0;
return 1 + getlog2(x / 2);
}
void fft(vector<cd>& a, bool inv) {
int n = (int)a.size(), k = getlog2(n);
for (int i = 0; i < n; i++) {
int j = 0;
for (int bit = 0; bit < k; bit++) {
if (i & (1 << bit)) {
j += (1 << (k - 1 - bit));
}
}
if (i < j) {
swap(a[i], a[j]);
}
}
for (int l = 2; l <= n; l *= 2) {
ld ang = 2 * PI / (ld)l;
if (inv) ang *= -1;
cd mlt(cos(ang), sin(ang));
for (int i = 0; i < n; i += l) {
cd cur(1);
for (int j = 0; j < l / 2; j++) {
cd x = a[i + j];
cd y = a[i + l / 2 + j] * cur;
a[i + j] = x + y;
a[i + l / 2 + j] = x - y;
cur *= mlt;
}
}
}
if (inv) {
for (auto& x : a) {
x /= n;
}
}
}
void conv_smart(vector<cd> a, vector<cd> b, vector<cd> &sol) {
int n = 1;
while (n <= (int)a.size() + (int)b.size()) n *= 2;
a.resize(n, 0);
b.resize(n, 0);
fft(a, 0);
fft(b, 0);
for (int i = 0; i < n; i++) {
a[i] *= b[i];
}
fft(a, 1);
sol.clear();
for (int i = 0; i < n; i++) {
sol.push_back(a[i]);
}
}
ld values[26];
const ld eps = 1e-6;
vector<cd> lol, cs, a;
vector<cd> reta, retb;
void place(string s, int len, vector<ld> &sol) {
sol.clear();
int n = (int) s.size();
if (len > n) {
return;
}
ld ang = 2 * PI / len;
cd c(cos(ang), sin(ang));
cs.resize(len);
a.resize(n);
cs[0] = 1;
for (int i = 1; i < len; i++) {
cs[i] = cs[i - 1] * c;
}
for (int i = 0; i < n; i++) {
a[i] = values[s[i] - 'a'];
}
sol.resize(n - len + 1);
conv_smart(cs, a, lol);
for (int i = 0; i < n - len + 1; i++) {
sol[i] = norm(lol[i + len - 1]);
}
}
string s, t;
vector<ld> norms_s, norms_t;
bool isok(int len) {
if (len > (int) s.size() || len > (int) t.size()) {
return 0;
}
int n = (int) s.size() - len + 1;
int m = (int) t.size() - len + 1;
norms_s.resize(n);
norms_t.resize(m);
for (int i = 0; i < n; i++) {
norms_s[i] = norm(reta[(len - 1) * ((int) s.size() + 2) + i]);
}
for (int i = 0; i < m; i++) {
norms_t[i] = norm(retb[(len - 1) * ((int) t.size() + 2) + i]);
}
sort(norms_s.begin(), norms_s.end());
sort(norms_t.begin(), norms_t.end());
int j = 0;
for (int i = 0; i < n; i++) {
while (j < m && norms_t[j] < norms_s[i]) {
j++;
}
if (0 <= j && j < m && abs(norms_s[i] - norms_t[j]) < eps) {
return 1;
}
if (0 <= j - 1 && j - 1 < m && abs(norms_s[i] - norms_t[j - 1]) < eps) {
return 1;
}
}
return 0;
}
void print(int len) {
int n = (int) s.size() - len + 1;
int m = (int) t.size() - len + 1;
norms_s.resize(n);
norms_t.resize(m);
for (int i = 0; i < n; i++) {
norms_s[i] = norm(reta[(len - 1) * ((int) s.size() + 2) + i]);
}
for (int i = 0; i < m; i++) {
norms_t[i] = norm(retb[(len - 1) * ((int) t.size() + 2) + i]);
}
for (int i = 0; i < n; i++) {
for (int j = 0; j < m; j++) {
if (abs(norms_s[i] - norms_t[j]) < eps) {
cout << i << " " << j << "\n";
exit(0);
}
}
}
}
vector<cd> cur;
void add(vector<cd> &v) {
for (auto &x : v) {
cur.push_back(x);
}
}
int main() {
for (int x = 0; x < 26; x++) {
values[x] = cos(rng()) * 10;
}
if (!home) {
verbose = 0;
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
if (home) {
verbose = 1;
freopen ("___input___.txt", "r", stdin);
}
cin >> s >> t;
int n = (int) s.size(), m = (int) t.size();
for (int len = 1; len <= n; len++) {
vector<cd> x(len);
ld ang = 2 * PI / len;
cd c(cos(ang), sin(ang));
x[0] = 1;
for (int i = 1; i < len; i++) {
x[i] = x[i - 1] * c;
}
for (int i = 0; i <= n - len; i++) {
x.push_back(0);
}
add(x);
}
{
a.resize(n);
for (int i = 0; i < n; i++) {
a[i] = values[s[i] - 'a'];
}
conv_smart(a, cur, reta);
}
cur.clear();
for (int len = 1; len <= m; len++) {
vector<cd> x(len);
ld ang = 2 * PI / len;
cd c(cos(ang), sin(ang));
x[0] = 1;
for (int i = 1; i < len; i++) {
x[i] = x[i - 1] * c;
}
for (int i = 0; i <= m - len; i++) {
x.push_back(0);
}
add(x);
}
{
a.resize(m);
for (int i = 0; i < m; i++) {
a[i] = values[t[i] - 'a'];
}
conv_smart(a, cur, retb);
}
for (int len = 1; len <= n; len++) {
place(s, len, norms_s);
for (int i = 0; i < n - len + 1; i++) {
cd l = lol[i + len - 1] - reta[(len - 1) * (n + 2) + i];
assert(abs(real(l)) < eps);
assert(abs(imag(l)) < eps);
}
}
int len = min(n, m);
while (!isok(len)) {
if (verbose) {
cout << "len = " << len << "\n";
}
len--;
}
cout << len << "\n";
print(len);
return 0;
}
Compilation message
necklace.cpp: In function 'int main()':
necklace.cpp:184:13: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
184 | freopen ("___input___.txt", "r", stdin);
| ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
11 ms |
1736 KB |
Output is correct |
| 2 |
Correct |
11 ms |
1856 KB |
Output is correct |
| 3 |
Correct |
8 ms |
1776 KB |
Output is correct |
| 4 |
Correct |
10 ms |
1364 KB |
Output is correct |
| 5 |
Correct |
11 ms |
1812 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
11 ms |
1736 KB |
Output is correct |
| 2 |
Correct |
11 ms |
1856 KB |
Output is correct |
| 3 |
Correct |
8 ms |
1776 KB |
Output is correct |
| 4 |
Correct |
10 ms |
1364 KB |
Output is correct |
| 5 |
Correct |
11 ms |
1812 KB |
Output is correct |
| 6 |
Correct |
220 ms |
23860 KB |
Output is correct |
| 7 |
Correct |
222 ms |
23840 KB |
Output is correct |
| 8 |
Correct |
176 ms |
19164 KB |
Output is correct |
| 9 |
Correct |
209 ms |
23828 KB |
Output is correct |
| 10 |
Correct |
216 ms |
23684 KB |
Output is correct |
| 11 |
Correct |
221 ms |
23680 KB |
Output is correct |
| 12 |
Correct |
208 ms |
23404 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
11 ms |
1736 KB |
Output is correct |
| 2 |
Correct |
11 ms |
1856 KB |
Output is correct |
| 3 |
Correct |
8 ms |
1776 KB |
Output is correct |
| 4 |
Correct |
10 ms |
1364 KB |
Output is correct |
| 5 |
Correct |
11 ms |
1812 KB |
Output is correct |
| 6 |
Correct |
220 ms |
23860 KB |
Output is correct |
| 7 |
Correct |
222 ms |
23840 KB |
Output is correct |
| 8 |
Correct |
176 ms |
19164 KB |
Output is correct |
| 9 |
Correct |
209 ms |
23828 KB |
Output is correct |
| 10 |
Correct |
216 ms |
23684 KB |
Output is correct |
| 11 |
Correct |
221 ms |
23680 KB |
Output is correct |
| 12 |
Correct |
208 ms |
23404 KB |
Output is correct |
| 13 |
Execution timed out |
1588 ms |
807876 KB |
Time limit exceeded |
| 14 |
Halted |
0 ms |
0 KB |
- |
