Submission #1294205

#	Time	Username	Problem	Language	Result	Execution time	Memory
1294205		thaibeo123	Pictionary (COCI18_pictionary)	C++20	140 / 140	125 ms	41748 KiB

pictionary

#include <bits/stdc++.h>
using namespace std;

#define NAME "A"
#define ll long long
#define fi first
#define se second
#define pb push_back
#define all(x) x.begin(), x.end()
#define MASK(x) (1ll << (x))
#define BIT(x, i) (((x) >> (i)) & 1)

const int N = 2e5 + 5;
const int LG = 19;

struct DSU {
    vector<int> lab;

    DSU(int n): lab(n + 1, -1) {}

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

    bool union_sets(int u, int v) {
        u = find_set(u);
        v = find_set(v);
        if (u == v) return 0;
        lab[u] += lab[v];
        lab[v] = u;
        return 1;
    }
};

int n, m, q, timer;
int L[N * 2][21], hi[N], ri[N];
vector<int> g[N];

int get(int u, int v) {
    int l = ri[u], r = ri[v];
    if (l > r) swap(l, r);
    int k = __lg(r - l + 1);
    u = L[l][k];
    v = L[r - MASK(k) + 1][k];
    return hi[u] < hi[v] ? u : v;
}

void dfs(int u) {
    L[++timer][0] = u;
    ri[u] = timer;
    for (int v : g[u]) {
        hi[v] = hi[u] + 1;
        dfs(v);
        L[++timer][0] = u;
    }
}

void input() {
    cin >> n >> m >> q;
}

void solve() {
    DSU dsu(n + m);
    for (int i = 1; i <= m; i++) {
        int x = m - i + 1;
        for (int j = x; j <= n; j += x) {
            int u = dsu.find_set(j);
            if (u != n + i) {
                g[n + i].pb(u);
                dsu.union_sets(n + i, u);
            }
        }
    }
    dfs(n + m);
    for (int j = 1; j <= LG; j++) {
        for (int i = 1; i + MASK(j) - 1 <= timer; i++) {
            int u = L[i][j - 1];
            int v = L[i + MASK(j - 1)][j - 1];
            L[i][j] = hi[u] < hi[v] ? u : v;
        }
    }
    while (q--) {
        int u, v;
        cin >> u >> v;
        cout << get(u, v) - n << "\n";
    }
}

signed main() {
    if (fopen(NAME".INP", "r")) {
        freopen(NAME".INP", "r", stdin);
        freopen(NAME".OUT", "w", stdout);
    }
    cin.tie(0)->sync_with_stdio(0);

    input();
    solve();

    return 0;
}

Compilation message (stderr)

pictionary.cpp: In function 'int main()':
pictionary.cpp:91:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         freopen(NAME".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
pictionary.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(NAME".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