| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1083466 | Joshua_Andersson | Necklace (Subtask 1-3) (BOI19_necklace1) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define int ll
const int inf = int(1e18);
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> p2;
#define rep(i, high) for (int i = 0; i < high; i++)
#define repp(i, low, high) for (int i = low; i < high; i++)
#define repe(i, container) for (auto& i : container)
#define sz(container) ((int)container.size())
#define all(x) begin(x),end(x)
inline void fast() { ios::sync_with_stdio(0); cin.tie(0); cout.tie(0); }
#if _LOCAL
#define assert(x) if (!(x)) __debugbreak()
#endif
typedef uint64_t ull;
struct H {
ull x; H(ull x = 0) : x(x) {}
H operator+(H o) { return x + o.x + (x + o.x < x); }
H operator-(H o) { return *this + ~o.x; }
H operator*(H o) {
auto m = (__uint128_t)x * o.x;
return H((ull)m) + (ull)(m >> 64);
}
ull get() const { return x + !~x; }
bool operator==(H o) const { return get() == o.get(); }
bool operator!=(H o) const { return !(*this == o); }
bool operator<(H o) const { return get() < o.get(); }
};
static const H C = (ll)1e11 + 3; // (order ~ 3e9; random also ok)
struct HashInterval {
vector<H> ha, pw;
HashInterval(string& str) : ha(sz(str) + 1), pw(ha) {
pw[0] = 1;
rep(i, 0, sz(str))
ha[i + 1] = ha[i] * C + str[i],
pw[i + 1] = pw[i] * C;
}
H hashInterval(int a, int b) { // hash [a, b)
b--;
return ha[b] - ha[a] * pw[b - a];
}
};
pair<int, p2> best(string a, string b, bool rev)
{
int ret = -1;
p2 r = p2(-1, -1);
HashInterval h1(a);
HashInterval h2(b);
mt19937 rng;
uniform_int_distribution<int> da(0, sz(a) - 1);
uniform_int_distribution<int> db(0, sz(b) - 1);
int l = 10;
auto start = chrono::high_resolution_clock::now();
while (chrono::duration_cast<chrono::milliseconds>(chrono::high_resolution_clock::now() - start).count() < 700)
{
int aa = da(rng);
int ab = aa;
int ba = db(rng);
int bb = ba;
int lo = -1;
int hi = 4001;
while (lo + 1 < hi)
{
int mid = (lo + hi) / 2;
if (aa + mid >= sz(a) || ba + mid >= sz(b) || h1.hashInterval(aa, aa + mid) != h2.hashInterval(ba, ba + mid))
{
hi = mid;
}
else lo = mid;
}
aa += hi;
ba += hi;
lo = -1;
hi = 4001;
while (lo + 1 < hi)
{
int mid = (lo + hi) / 2;
if (ab - 1 - mid < 0 || bb - 1 - mid < 0 || h1.hashInterval(ab - 1 - mid, ab - 1) != h2.hashInterval(bb - 1 - mid, bb - 1))
{
hi = mid;
}
else lo = mid;
}
ab -= hi;
bb -= hi;
//startb = sb;
//startb = sb;
//assert(starta != 1830);
int starta = aa;
int startb = bb;
if (rand() % 2)
{
starta = ab;
startb = ba;
}
int rp = 0;
repp(rlen, 1, l * 2 + 1)
{
int i = starta - rlen;
int j = startb;
if (i < 0 || j + rlen - 1 >= sz(b)) break;
bool good = h1.hashInterval(i, i + rlen - 1) == h2.hashInterval(j, j + rlen - 1);
if (good) rp = rlen;
}
int lp = 0;
repp(llen, 1, l * 2 + 1)
{
int i = starta;
int j = startb - llen;
if (j < 0 || i + llen - 1 >= sz(a)) break;
bool good = h1.hashInterval(i, i + llen - 1) == h2.hashInterval(j, j + llen - 1);
if (good) lp = llen;
}
if (rp + lp > ret)
{
//assert(rp + lp != 84);
r = { starta - rp,startb - lp };
if (rev) r.second = sz(b) - r.second - rp - lp;
//assert(r != p2(18, 54));
ret = rp + lp;
l = max(l, ret);
}
}
return { ret, r };
}
signed main()
{
fast();
string a, b;
cin >> a >> b;
pair<int, p2> ans = { -1000,p2(0,0) };
ans = max(ans, best(a, b, 0));
reverse(all(b));
ans = max(ans, best(a, b, 1));
cout << ans.first << "\n" << ans.second.first << " " << ans.second.second;
return 0;
}