Submission #713695

#	Time	Username	Problem	Language	Result	Execution time	Memory
713695		tamyte	Tax Evasion (LMIO19_mokesciai)	C++14	100 / 100	437 ms	55668 KiB

mokesciai

#include <bits/stdc++.h>


using namespace std;
#define sz(x) (int)(x).size()
void setIO(string name = "")
{
    cin.tie(0)->sync_with_stdio(0); // see /general/fast-io
    if (sz(name))
    {
        freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
        freopen((name + ".out").c_str(), "w", stdout);
    }
}

/*----------------------------------*/
const int MAXN = 2e5 + 10, maxLog = 32;

int n, m, dep[MAXN] {0}, par[MAXN][maxLog] = {0}, best[MAXN];

vector<int> adj[MAXN];



void dfs(int v, int u) {
    dep[v] = dep[u] + 1;
    par[v][0] = u;
    for (auto i : adj[v]) {
        if (i == u) continue;
        dfs(i, v);
    }
}

int lift(int p, int x) {
    for (int i = 0; i < maxLog; ++i) {
        if (x & (1 << i)) {
            p = par[p][i];
        }
    }
    return p;
}
bool pos = true;

int possible(int v, int u, int val) {
    int cnt = 0;
    for (auto i : adj[v]) {
        if (i == u) continue;
        cnt += possible(i, v, val);
    }
    if (dep[v] >= val - 1) cnt++;
    if (cnt < best[v]) pos = false;
    cnt -= best[v];
    return cnt;
}

int solve() {
    int l = 0, r = n;
    while (l < r - 1) {
        int m = l + (r - l) / 2;
        pos = true;
        possible(1, 0, m);
        if (pos) l = m;
        else r = m - 1;
    }
    pos = true;
    possible(1, 0, r + 1);
    if (pos) return r + 1;
    pos = true;
    possible(1, 0, r);
    if (pos) return r;
    return r - 1;
}



int main()
{
    setIO("");
    cin >> n >> m;
    for (int i = 2; i <= n; ++i) {
        int a;
        cin >> a;
        adj[a].push_back(i);
        adj[i].push_back(a);
    }
    dep[0] = -1;
    par[0][0] = 0;
    dfs(1, 0);
    // cerr << "a\n";
    for (int i = 1; i < maxLog; ++i) {
        for (int x = 1; x <= n; ++x) {
            par[x][i] = par[par[x][i - 1]][i - 1];
        }
    }
    // cerr << "a\n";
    for (int i = 0; i < m; ++i) {
        int a;
        cin >> a;
        best[lift(a, (dep[a] - 1) / 2)]++;
    }
    cout << solve();
}

Compilation message (stderr)

mokesciai.cpp: In function 'void setIO(std::string)':
mokesciai.cpp:11:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   11 |         freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mokesciai.cpp:12:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   12 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 22 / 22
• Subtask 3: 39 / 39
• Subtask 4: 29 / 29