Submission #383083

#	Time	Username	Problem	Language	Result	Execution time	Memory
383083		smax	Untitled (POI11_dyn)	C++17	100 / 100	1484 ms	33556 KiB

Main

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

#ifdef LOCAL
#define DEBUG(...) debug(#__VA_ARGS__, __VA_ARGS__)
#else
#define DEBUG(...) 6
#endif

template<typename T, typename S> ostream& operator << (ostream &os, const pair<T, S> &p) {return os << "(" << p.first << ", " << p.second << ")";}
template<typename C, typename T = decay<decltype(*begin(declval<C>()))>, typename enable_if<!is_same<C, string>::value>::type* = nullptr>
ostream& operator << (ostream &os, const C &c) {bool f = true; os << "["; for (const auto &x : c) {if (!f) os << ", "; f = false; os << x;} return os << "]";}
template<typename T> void debug(string s, T x) {cerr << s << " = " << x << "\n";}
template <typename T, typename... Args> void debug(string s, T x, Args... args) {for (int i=0, b=0; i<(int)s.size(); i++) if (s[i] == '(' || s[i] == '{') b++; else
if (s[i] == ')' || s[i] == '}') b--; else if (s[i] == ',' && b == 0) {cerr << s.substr(0, i) << " = " << x << " | "; debug(s.substr(s.find_first_not_of(' ', i + 1)), args...); break;}}

const int INF = 1e9;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    int n, m;
    cin >> n >> m;
    vector<int> d(n);
    for (int i=0; i<n; i++)
        cin >> d[i];
    vector<vector<int>> adj(n);
    for (int i=0; i<n-1; i++) {
        int a, b;
        cin >> a >> b;
        a--, b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }

    int k, cnt;

    auto dfs = [&] (auto &self, int u, int p) -> int {
        int ret = d[u] ? 0 : INF;
        for (int v : adj[u])
            if (v != p) {
                int d = self(self, v, u);
                if (ret > d)
                    swap(ret, d);
                if (ret <= 0 && d > 0 && d - ret <= k)
                    ret = d;
            }
        if (ret == -k) {
            cnt++;
            ret = 1;
        } else if (ret <= 0) {
            ret--;
        } else {
            ret++;
        }
        return ret;
    };

    int l = 0, r = n;
    while (l < r) {
        k = (l + r) / 2;
        cnt = 0;
        if (dfs(dfs, 0, -1) < 0)
            cnt++;
        if (cnt <= m)
            r = k;
        else
            l = k + 1;
    }
    cout << l << "\n";

    return 0;
}

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