Submission #454250

#	Time	Username	Problem	Language	Result	Execution time	Memory
454250		HillcrestEnigma	Paprike (COI18_paprike)	C++17	100 / 100	91 ms	19084 KiB

paprike

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;

#pragma GCC optimize("Ofast")
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
/* #define endl '\n' */
#define indexed_set tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update>
using ll = long long;
using vi = vector<int>;
using vvi = vector<vi>;
using pii = pair<int, int>;
using vpii = vector<pair<int, int>>;
const int MOD = 1e9+7;
const int dx[4] = {1, 0, -1, 0}, dy[4] = {0, -1, 0, 1};

int n, k, a, b;
int ans = 0;
int h[100000] = {0};
vi graph[100000];

int dfs(int v, int p) {
    vi spy;

    /* cout << v << ": "; */
    /* for (int c:graph[v]) cout << c << " "; */
    /* cout << endl; */

    for (int c:graph[v]) if (c != p) spy.push_back(dfs(c, v));
    sort(all(spy));

    int res = h[v];
    for (int i=0; i<spy.size(); i++) {
        if (res + spy[i] > k) {
            ans += spy.size() - i;
            return res;
        }
        res += spy[i];
    }
    return res;
}

void _main() {
    cin >> n >> k;

    for (int i=0; i<n; i++) {
        cin >> h[i];
    }

    for (int i=0; i<n-1; i++) {
        cin >> a >> b;
        --a; --b;
        graph[a].push_back(b);
        graph[b].push_back(a);
    }

    dfs(0, -1);

    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    _main();
    return 0;
}

Compilation message (stderr)

paprike.cpp: In function 'int dfs(int, int)':
paprike.cpp:35:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |     for (int i=0; i<spy.size(); i++) {
      |                   ~^~~~~~~~~~~

• Subtask 1: 11 / 11
• Subtask 2: 13 / 13
• Subtask 3: 27 / 27
• Subtask 4: 49 / 49