Submission #1338724

#	Time	Username	Problem	Language	Result	Execution time	Memory
1338724		vuviet	Pictionary (COCI18_pictionary)	C++20	140 / 140	112 ms	6668 KiB

pictionary

/**
 *     Author:       trviet
 *     Studies at:   Le Hong Phong High School for the Gifted
**/

#include <bits/stdc++.h>

#define ____vuviet__ signed main
#define taskname "trviet"

using namespace std;

constexpr int N = 1e5 + 5;
int n, m, q, lo[N], hi[N], res[N], a[N], b[N];

struct DisjointSets
{
    int sz;
    vector<int> lab;

    DisjointSets(int sz)
    {
        this->sz = sz;
        lab.resize(sz + 1, -1);
    }

    int findset(int u)
    {
        return lab[u] < 0 ? u : lab[u] = findset(lab[u]);
    }

    void unite(int r, int s)
    {
        r = findset(r), s = findset(s);
        if (r == s) return;
        if (lab[r] > lab[s]) swap(r, s);
        lab[r] += lab[s], lab[s] = r;
    }
};

void ReadData()
{
    cin >> n >> m >> q;
    for (int i = 1; i <= q; ++i)
    {
        cin >> a[i] >> b[i];
        lo[i] = 1, hi[i] = m;
    }
}

int lg2(int x)
{
    int cnt = 0;
    while (x > 0)
        ++cnt, x /= 2;
    return cnt - 1;
}

void solvebytrvietbels()
{
    ReadData();
    int log2 = lg2(m + 1);
    for (int t = 0; t < log2 + 1; ++t)
    {
        vector<vector<int>> queries(m + 1);
        for (int i = 1; i <= q; ++i)
            if (lo[i] <= hi[i])
                queries[(lo[i] + hi[i]) / 2].push_back(i);
        DisjointSets dsu(n + 5);
        for (int g = m; g >= 1; --g)
        {
            for (int k = g * 2; k <= n; k += g)
                dsu.unite(g, k);
            for (int id : queries[g])
            {
                if (dsu.findset(a[id]) == dsu.findset(b[id])) {
                    res[id] = g, lo[id] = g + 1;
                } else {
                    hi[id] = g - 1;
                }
            }
        }
    }
    for (int i = 1; i <= q; ++i)
    {
        int days = m - res[i] + 1;
        cout << days << "\n";
    }
}

void freopen_stdio(string speech)
{
    cin.tie(0)->sync_with_stdio(0);
    cerr << speech << "\n";
    if (fopen(taskname ".inp", "r"))
    {
        freopen(taskname ".inp", "r", stdin);
        freopen(taskname ".out", "w", stdout);
    }
}

____vuviet__()
{
    freopen_stdio("...miss you...");
    int t = 1;
    // cin >> t;
    while (t-- > 0)
        solvebytrvietbels();
    return 0;
}

Compilation message (stderr)

pictionary.cpp: In function 'void freopen_stdio(std::string)':
pictionary.cpp:97:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   97 |         freopen(taskname ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pictionary.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(taskname ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 14 / 14
• Subtask 2: 14 / 14
• Subtask 3: 14 / 14
• Subtask 4: 14 / 14
• Subtask 5: 14 / 14
• Subtask 6: 14 / 14
• Subtask 7: 14 / 14
• Subtask 8: 14 / 14
• Subtask 9: 14 / 14
• Subtask 10: 14 / 14