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Submission #156351

# Submission time Handle Problem Language Result Execution time Memory
156351 2019-10-05T09:48:58 Z ryansee Necklace (Subtask 1-3) (BOI19_necklace1) C++14
85 / 85
 1286 ms 632 KB 
#include "bits/stdc++.h"
using namespace std;

#define FAST ios_base::sync_with_stdio(false); cin.tie(0);
#define pb push_back
#define eb emplace_back
#define ins insert
#define ph push
#define f first
#define s second
#define cbr cerr << "hi\n"
#define mmst(x, v) memset((x), v, sizeof ((x)))
#define siz(x) ((ll)x.size())
#define all(x) (x).begin(), (x).end()
#define lbd(x, y) lower_bound(all(x), y)
#define ubd(x, y) upper_bound(all(x), y)
#define btinpct(x) __builtin_popcountll((x))
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());    //can be used by calling rng() or shuffle(A, A+n, rng)
inline long long rand(long long x, long long y) { return (rng() % (y+1-x)) + x; } //inclusivesss
string to_string(char c) {string s(1,c);return s;} template<typename T> inline T gcd(T a,T b){ return a==0?b:gcd(b%a,a); }

#define ll long long int 
#define ld long double
#define FOR(ii, ss, ee) for(ll ii = (ss); ii <= (ll)(ee); ++ii)
#define DEC(ii, ss, ee) for(ll ii = (ss); ii >= (ll)(ee); --ii)
typedef pair <ll, ll> pi; typedef pair <ll, pi> spi; typedef pair <pi, pi> dpi;

#define LLINF ((long long) 1e18)//1234567890987654321
#define INF 1234567890ll
// #define cerr if(0)cout
#define MAXN (3006)
string A[2];
const ll mod=1e9+9;
const ll base=37;
ll pw[MAXN];
ll s[2], ans=0, l[2], r[2], n[2]; bool rev;
void solve() {
	auto start = chrono::high_resolution_clock::now();
	while(1) {
		auto finish=chrono::high_resolution_clock::now();
		chrono::duration<ld> elapsed=finish-start;
		if(elapsed.count() > (ld)0.65) break;
		FOR(i,0,1) {
			l[i]=rand(0, n[i]-1);
			r[i]=l[i];
		}
		if(A[0][l[0]]!=A[1][l[1]] || 2*(min(l[0],l[1])+min(n[0]-r[0]-1, n[1]-r[1]-1)) <= ans) continue;
		while(min(l[0],l[1]) > 0 && A[0][l[0]-1]==A[1][l[1]-1]) --l[0], --l[1];
		while(r[0]+1 < n[0] && r[1]+1 < n[1] && A[0][r[0]+1]==A[1][r[1]+1]) ++r[0], ++r[1];
		ll len=r[0]-l[0]+1;
		if(2*len <= ans) continue;
		if(len > ans) {
			ans=len;
			tie(s[0],s[1])=tie(l[0],l[1]);
			if(rev) s[1]=n[1]-r[1]-1;
		}
		FOR(i,0,1) {
			vector<ll> hash(2, 0);
			FOR(j,1,len) {
				if(r[i] + j >= n[i] || l[!i] - j < 0) break;
				hash[i]+=(ll)(A[i][r[i]+j]-'a')*pw[j-1]%mod;
				hash[i]%=mod;
				hash[!i]*=base, hash[!i]%=mod;
				hash[!i]+=(ll)(A[!i][l[!i]-j]-'a'), hash[!i]%=mod;
				if(hash[i] == hash[!i] && len+j > ans){
					ans=len+j;
					s[0]=l[i];
					s[1]=l[!i]-j;
					if(i) swap(s[0],s[1]);
					if(rev) s[1]=n[1]-r[1]-(i?j:0)-1;
					// if(s[1] == 6 && rev) cerr<<n[1]<<' '<<l[1]<<' '<<r[1]<<' '<<i<<' '<<j<<'\n';
				}
			}
		}
	}
}
int main()
{
	FAST
	cin>>A[0]>>A[1];
	n[0]=A[0].size(), n[1]=A[1].size();
	pw[0]=1; FOR(i,1,MAXN-1) pw[i]=pw[i-1]*base%mod;
	solve();
	reverse(all(A[1]));rev=1;
	solve();
	assert(ans), cout<<ans<<'\n'<<s[0]<<' '<<s[1]<<'\n';
}

Subtask #1
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1272 ms 504 KB Output is correct
2 Correct 1264 ms 408 KB Output is correct
3 Correct 1283 ms 412 KB Output is correct
4 Correct 1286 ms 376 KB Output is correct
5 Correct 1268 ms 408 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1272 ms 504 KB Output is correct
2 Correct 1264 ms 408 KB Output is correct
3 Correct 1283 ms 412 KB Output is correct
4 Correct 1286 ms 376 KB Output is correct
5 Correct 1268 ms 408 KB Output is correct
6 Correct 1269 ms 412 KB Output is correct
7 Correct 1278 ms 376 KB Output is correct
8 Correct 1271 ms 412 KB Output is correct
9 Correct 1268 ms 404 KB Output is correct
10 Correct 1256 ms 544 KB Output is correct
11 Correct 1281 ms 408 KB Output is correct
12 Correct 1275 ms 632 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1272 ms 504 KB Output is correct
2 Correct 1264 ms 408 KB Output is correct
3 Correct 1283 ms 412 KB Output is correct
4 Correct 1286 ms 376 KB Output is correct
5 Correct 1268 ms 408 KB Output is correct
6 Correct 1269 ms 412 KB Output is correct
7 Correct 1278 ms 376 KB Output is correct
8 Correct 1271 ms 412 KB Output is correct
9 Correct 1268 ms 404 KB Output is correct
10 Correct 1256 ms 544 KB Output is correct
11 Correct 1281 ms 408 KB Output is correct
12 Correct 1275 ms 632 KB Output is correct
13 Correct 1270 ms 428 KB Output is correct
14 Correct 1273 ms 432 KB Output is correct
15 Correct 1224 ms 424 KB Output is correct
16 Correct 1252 ms 504 KB Output is correct
17 Correct 1272 ms 504 KB Output is correct
18 Correct 1250 ms 504 KB Output is correct
19 Correct 1285 ms 428 KB Output is correct
20 Correct 1268 ms 420 KB Output is correct
21 Correct 1272 ms 508 KB Output is correct