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Submission #1081232

# Submission time Handle Problem Language Result Execution time Memory
1081232 2024-08-29T20:01:39 Z Joshua_Andersson Necklace (Subtask 1-3) (BOI19_necklace1) C++14
45 / 85
 1500 ms 70996 KB 
#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 unsigned long long ull;

struct RollingHash
{
    vector<ull> suf, b;
    int mod;
    RollingHash(string& s, ull base = 131, ull mod = 1e9 + 7) : mod(mod), suf(s.size() + 1), b(s.size() + 1)
    {
        b[0] = 1;
        b[1] = base;

        for (int i = sz(s) - 1; i >= 0; i--)
        {
            suf[i] = (suf[i + 1] * base + s[i]) % mod;
        }

        repp(i, 2, s.size() + 1)
        {
            b[i] = b[i - 1] * b[1] % mod;
        }
    }

    ull gethash(int l, int r) // hash s[l, r]
    {
        ull rv = (suf[r + 1] * b[r - l + 1]) % mod;
        return suf[l] + mod * (suf[l] < rv) - rv;
    }
};

struct DoubleHash
{
    RollingHash h1;
    RollingHash h2;
    DoubleHash(string& s, ull mod = 1e9 + 7) : h1(s, 157, mod), h2(s, 131, mod) {}
    ull gethash(int l, int r)
    {
        return (h1.gethash(l, r) << 32) + h2.gethash(l, r);
    }
};

pair<int,p2> best(string a, string b, bool rev)
{
    int ret = -1;
    p2 r = p2(-1, -1);
    vvi lcp(sz(a), vi(sz(b)));
    DoubleHash h1(a);
    DoubleHash h2(b);
    rep(starta, sz(a))
    {
        rep(startb, sz(b))
        {
            int rp = 0;
            repp(rlen, 1, 1000)
            {
                int i = starta - rlen;
                int j = startb;
                if (i<0||j+rlen -1 >= sz(b)) break;
                bool good = h1.gethash(i, i + rlen - 1) == h2.gethash(j, j + rlen - 1);
                if (good) rp = rlen;
            }
            int lp = 0;
            repp(llen, 1, 1000)
            {
                int i = starta;
                int j = startb - llen;
                if (j < 0 || i + llen - 1 >= sz(a)) break;
                bool good = h1.gethash(i, i + llen - 1) == h2.gethash(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;
                ret = rp+lp;
            }
        }
    }
    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;
}

Compilation message

necklace.cpp: In constructor 'RollingHash::RollingHash(std::string&, ull, ull)':
necklace.cpp:29:9: warning: 'RollingHash::mod' will be initialized after [-Wreorder]
   29 |     int mod;
      |         ^~~
necklace.cpp:28:17: warning:   'std::vector<long long unsigned int> RollingHash::suf' [-Wreorder]
   28 |     vector<ull> suf, b;
      |                 ^~~
necklace.cpp:30:5: warning:   when initialized here [-Wreorder]
   30 |     RollingHash(string& s, ull base = 131, ull mod = 1e9 + 7) : mod(mod), suf(s.size() + 1), b(s.size() + 1)
      |     ^~~~~~~~~~~
necklace.cpp:13:48: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 | #define repp(i, low, high) for (int i = low; i < high; i++)
......
   40 |         repp(i, 2, s.size() + 1)
      |              ~~~~~~~~~~~~~~~~~~                 
necklace.cpp:40:9: note: in expansion of macro 'repp'
   40 |         repp(i, 2, s.size() + 1)
      |         ^~~~

Subtask #1
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 348 KB Output is correct
2 Correct 13 ms 540 KB Output is correct
3 Correct 9 ms 348 KB Output is correct
4 Correct 9 ms 460 KB Output is correct
5 Correct 12 ms 348 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 348 KB Output is correct
2 Correct 13 ms 540 KB Output is correct
3 Correct 9 ms 348 KB Output is correct
4 Correct 9 ms 460 KB Output is correct
5 Correct 12 ms 348 KB Output is correct
6 Correct 797 ms 1728 KB Output is correct
7 Correct 791 ms 1720 KB Output is correct
8 Correct 602 ms 1444 KB Output is correct
9 Correct 742 ms 1628 KB Output is correct
10 Correct 775 ms 1628 KB Output is correct
11 Correct 770 ms 1696 KB Output is correct
12 Correct 720 ms 1624 KB Output is correct

Subtask #3
0.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 348 KB Output is correct
2 Correct 13 ms 540 KB Output is correct
3 Correct 9 ms 348 KB Output is correct
4 Correct 9 ms 460 KB Output is correct
5 Correct 12 ms 348 KB Output is correct
6 Correct 797 ms 1728 KB Output is correct
7 Correct 791 ms 1720 KB Output is correct
8 Correct 602 ms 1444 KB Output is correct
9 Correct 742 ms 1628 KB Output is correct
10 Correct 775 ms 1628 KB Output is correct
11 Correct 770 ms 1696 KB Output is correct
12 Correct 720 ms 1624 KB Output is correct
13 Execution timed out 1556 ms 70996 KB Time limit exceeded
14 Halted 0 ms 0 KB -