Submission #525114

#	Time	Username	Problem	Language	Result	Execution time	Memory
525114		LeticiaFCS	Necklace (Subtask 4) (BOI19_necklace4)	C++17	0 / 15	289 ms	388 KiB

necklace

#include "bits/stdc++.h"
#define st first
#define nd second
using lint = int64_t;
constexpr int MOD = int(1e9) + 7;
constexpr int INF = 0x3f3f3f3f;
constexpr int NINF = 0xcfcfcfcf;
constexpr lint LINF = 0x3f3f3f3f3f3f3f3f;
const long double PI = acosl(-1.0);
// Returns -1 if a < b, 0 if a = b and 1 if a > b.
int cmp_double(double a, double b = 0, double eps = 1e-9) {
	return a + eps > b ? b + eps > a ? 0 : 1 : -1;
}
using namespace std;


vector<int> kmp(const string &s){
	int n = int(s.size());
	vector<int> pi(n);
	for(int i=1; i<n; i++){
		pi[i] = pi[i-1];
		while(pi[i] && s[i] != s[ pi[i] ])
			pi[i] = pi[ pi[i]-1 ];
		if( s[i] == s[ pi[i] ])
			pi[i]++;
	}
	return pi;
 
}
int ans = 0, ans1=0, ans2=0;

void solve(const string &s, const string & t, bool rev = false){
	int n = int(s.size());
	int m = int(t.size());
	string tr = t;
	reverse(begin(tr), end(tr));
	for(int p=0;p<=n; p++){
			string a = s.substr(0, p);
			string b = s.substr(p, n);
			//cout<<a<<" "<<b<<"\n";
			reverse(begin(a),  end(a));
			auto pi1 = kmp(a+"#"+tr);
			auto pi2 = kmp(b+"#"+t);
			
			for(int j=p+1; j+1<p+1+m; j++){
				int j2 = j - (p+1);
				int k = m-1-(j2+1);
				k += int(b.size()+1);
				int cur = pi1[j] + pi2[k]; 
				if(cur > ans){
					ans = cur;
					ans1 = p;
					ans2 = j2;
					if(rev) ans2 = (m-1-ans2) - cur;
				}
				//cout<<pi1[j] + pi2[k]<<"  "<<j2<<" "<<k<<"\n";
			}		
	}
	

}

int main() {
	cin.tie(nullptr)->sync_with_stdio(false);
	//int __; cin >> __; for( int _ = 1 ; _ <= __ ; _++ ){ }
	string s, t;
	cin>>s>>t;	
	solve(s, t);
	reverse(t.begin(), t.end());
	solve(s, t, true);
	cout<<ans<<"\n"<<ans1<<" "<<ans2<<"\n";
	return 0;
}
/*
[  ]Leu o problema certo???
[  ]Ver se precisa de long long
[  ]Viu o limite dos fors (é n? é m?)
[  ]Tamanho do vetor, será que é 2e5 em vez de 1e5??
[  ]Testar sample
[  ]Testar casos de  borda
[  ]1LL no 1LL << i
[  ]Testar mod (é 1e9+7, mesmo?, será que o mod não ficou negativo?)
*/

• Subtask 1: 0 / 15