#include <bits/stdc++.h>
using namespace std;
#define int int64_t //be careful about this
#define endl "\n"
#define f(i,a,b) for(int i=int(a);i<int(b);++i)
#define pr pair
#define ar array
#define fr first
#define sc second
#define vt vector
#define pb push_back
#define eb emplace_back
#define LB lower_bound
#define UB upper_bound
#define PQ priority_queue
#define SZ(x) ((int)(x).size())
#define all(a) (a).begin(),(a).end()
#define allr(a) (a).rbegin(),(a).rend()
#define mem(a,b) memset(a, b, sizeof(a))
template<class A> void rd(vt<A>& v);
template<class T> void rd(T& x){ cin >> x; }
template<class H, class... T> void rd(H& h, T&... t) { rd(h) ; rd(t...) ;}
template<class A> void rd(vt<A>& x) { for(auto& a : x) rd(a) ;}
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
void setIO(string s = "") {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
// remove this when size of input is not fixed.
cin.exceptions(cin.failbit);
cout.precision(15); cout << fixed;
if(SZ(s)){
freopen((s+".in").c_str(),"r",stdin);
freopen((s+".out").c_str(),"w",stdout);
}
}
namespace kmp {
// Returns the next length to search from after starting from `len` and adding char `c`.
// Runs in worst case O(len) but amortizes to O(1) in most situations.
template<typename T, typename T_elem>
int get_link(const T &pattern, const vector<int> &fail, int len, const T_elem &c) {
while(len > 0 && pattern[len] != c) len = fail[len];
if(pattern[len] == c) len++;
return len;
}
// Computes the failure function on `pattern` so that we can search for it in future strings.
template<typename T>
vector<int> compute_failure_function(const T &pattern) {
// fail[i] = for the prefix [0, i) of `pattern`, the length of the longest proper prefix that is also a suffix.
int n = int(pattern.size());
vector<int> fail(n + 1, 0);
int len = 0;
for(int i = 1; i < n; i++) {
len = get_link(pattern, fail, len, pattern[i]);
fail[i + 1] = len;
}
return fail;
}
}
const char DELIMITER = '#';
void solve(const string s,const string t, int& max_length, int& start_s, int& start_t, bool reversed_t){
int n = SZ(s), m = SZ(t);
string sa, sb;
vt<int> va, vb;
for(int i = 0; i <= n; ++i){
sa.clear(); sb.clear();
va.clear(); vb.clear();
for(int j = i; j < n; ++j) sa.pb(s[j]);
sa.pb(DELIMITER);
sa += t;
sb = t;
sb.pb(DELIMITER);
for(int j = 0; j < i; ++j) sb.pb(s[j]);
reverse(all(sb));
va = kmp::compute_failure_function(sa);
vb = kmp::compute_failure_function(sb);
int x = i, y = n - i;
for(int j = 0; j <= m; ++j){
int tmp = va[y+1+j] + vb[x+1+m-j];
if(ckmax(max_length,tmp)){
start_s = i - vb[x+1+m-j];
start_t = j - va[y+1+j];
if(reversed_t){
int end_t = j + vb[x+1+m-j] - 1;
start_t = m - 1 - end_t;
}
}
}
}
return;
}
signed main(){
setIO();
string s,t;
rd(s,t);
int max_length = 0, start_s = -1, start_t = -1;
solve(s,t,max_length,start_s,start_t,false);
reverse(all(t));
solve(s,t,max_length,start_s,start_t,true);
cout << max_length << endl;
cout << start_s << ' ' << start_t;
}
Compilation message
necklace.cpp: In function 'void setIO(std::string)':
necklace.cpp:39:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
39 | freopen((s+".in").c_str(),"r",stdin);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
necklace.cpp:40:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
40 | freopen((s+".out").c_str(),"w",stdout);
| ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
325 ms |
460 KB |
Output is correct |
| 2 |
Correct |
297 ms |
464 KB |
Output is correct |
| 3 |
Correct |
331 ms |
476 KB |
Output is correct |
| 4 |
Correct |
252 ms |
460 KB |
Output is correct |
| 5 |
Correct |
269 ms |
468 KB |
Output is correct |
| 6 |
Correct |
290 ms |
460 KB |
Output is correct |
| 7 |
Correct |
272 ms |
496 KB |
Output is correct |
| 8 |
Correct |
288 ms |
492 KB |
Output is correct |
| 9 |
Correct |
291 ms |
504 KB |
Output is correct |
