// Copyright © 2022 Youngmin Park. All rights reserved.
//#pragma GCC optimize("O3")
//#pragma GCC target("avx2")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vi = vector<int>;
using pii = pair<int, int>;
using vpi = vector<pii>;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vpl = vector<pll>;
using ld = long double;
template <typename T, size_t SZ>
using ar = array<T, SZ>;
template <typename T>
using pqg = priority_queue<T, vector<T>, greater<T>>;
#define all(v) (v).begin(), (v).end()
#define pb push_back
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
constexpr int INF = 1e9;
constexpr ll LINF = 1e18;
const ld PI = acos((ld)-1.0);
constexpr int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
template <typename T>
constexpr bool ckmin(T &a, const T &b) { return b < a ? a = b, 1 : 0; }
template <typename T>
constexpr bool ckmax(T &a, const T &b) { return b > a ? a = b, 1 : 0; }
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); } // divide a by b rounded down
#ifdef LOCAL
#include "miscellaneous/debug.h"
#else
#define dbg(...) 42
#endif
inline namespace RecursiveLambda {
template <typename Fun>
struct y_combinator_result {
Fun fun_;
template <typename T>
explicit constexpr y_combinator_result(T &&fun) : fun_(forward<T>(fun)) {}
template <typename... Args>
constexpr decltype(auto) operator()(Args &&...args) const {
return fun_(ref(*this), forward<Args>(args)...);
}
};
template <typename Fun>
decltype(auto) y_combinator(Fun &&fun) {
return y_combinator_result<decay_t<Fun>>(forward<Fun>(fun));
}
};
/**
* Description: Knuth-Morris-Pratt Algorithm
* Source: Academic paper
* Verification: CSES 1753 - https://cses.fi/problemset/task/1753
* Time complexity - O(n), n = length of the string
*/
vi kmp(const string& s) {
int n = sz(s);
vi pi(n);
for (int i = 1, j = 0; i < n; i++) {
while (j && s[i] != s[j]) {
j = pi[j - 1];
}
if (s[i] == s[j]) j++;
pi[i] = j;
}
return pi;
}
void solve() {
string s, t;
cin >> s >> t;
pii ans{};
int global_max{};
for (int iter = 0; iter < 2; iter++, reverse(all(t))) {
pii cur{};
int cur_max{};
for (int i = 0; i < sz(s); i++) {
string r(s.begin(), s.begin() + i + 1);
reverse(all(r));
reverse(all(t));
r += '#';
r += t;
vi pi_a = kmp(r);
dbg("0~i:", r);
string().swap(r);
reverse(all(t));
r = {s.begin() + i + 1, s.end()};
r += '#';
r += t;
vi pi_b = kmp(r);
dbg("i+1~n-1:", r);
for (int j = 0; j < sz(t); j++) {
int blen = pi_b[sz(s)-i+j];
int alen = pi_a[sz(t)+i-j];
if (ckmax(cur_max, alen+blen)) {
dbg(i, j, alen, blen, iter);
cur = {i-alen+1, j-blen+1};
}
}
string().swap(r);
vi().swap(pi_a);
vi().swap(pi_b);
}
if (ckmax(global_max, cur_max)) {
if (iter == 0) ans = cur;
else {
dbg(cur, sz(t));
// int tt = sz(t) - 1 - cur.se;
cur.se += cur_max - 1;
cur.se = sz(t) - 1 - cur.se;
ans = cur;
}
}
}
cout << global_max << '\n';
cout << ans.fi << ' ' << ans.se << '\n';
}
int main() {
cin.tie(0)->sync_with_stdio(0);
cin.exceptions(cin.failbit);
int testcase = 1;
// cin >> testcase;
while (testcase--) {
solve();
}
#ifdef LOCAL
cerr << "Time elapsed: " << 1.0 * (double)clock() / CLOCKS_PER_SEC << " s.\n";
#endif
}
Compilation message
necklace.cpp: In function 'void solve()':
necklace.cpp:43:18: warning: statement has no effect [-Wunused-value]
43 | #define dbg(...) 42
| ^~
necklace.cpp:100:4: note: in expansion of macro 'dbg'
100 | dbg("0~i:", r);
| ^~~
necklace.cpp:43:18: warning: statement has no effect [-Wunused-value]
43 | #define dbg(...) 42
| ^~
necklace.cpp:107:4: note: in expansion of macro 'dbg'
107 | dbg("i+1~n-1:", r);
| ^~~
necklace.cpp:43:18: warning: statement has no effect [-Wunused-value]
43 | #define dbg(...) 42
| ^~
necklace.cpp:112:6: note: in expansion of macro 'dbg'
112 | dbg(i, j, alen, blen, iter);
| ^~~
necklace.cpp:43:18: warning: statement has no effect [-Wunused-value]
43 | #define dbg(...) 42
| ^~
necklace.cpp:123:5: note: in expansion of macro 'dbg'
123 | dbg(cur, sz(t));
| ^~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
187 ms |
528 KB |
Output is correct |
| 2 |
Correct |
149 ms |
384 KB |
Output is correct |
| 3 |
Correct |
238 ms |
408 KB |
Output is correct |
| 4 |
Correct |
147 ms |
400 KB |
Output is correct |
| 5 |
Correct |
122 ms |
340 KB |
Output is correct |
| 6 |
Correct |
154 ms |
400 KB |
Output is correct |
| 7 |
Correct |
145 ms |
516 KB |
Output is correct |
| 8 |
Correct |
164 ms |
412 KB |
Output is correct |
| 9 |
Correct |
177 ms |
404 KB |
Output is correct |
