Submission #48463

#	Time	Username	Problem	Language	Result	Execution time	Memory
48463		WLZ	Paprike (COI18_paprike)	C++17	13 / 100	72 ms	20108 KiB

paprike

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

typedef pair<int, int> ii;
typedef long long ll;
const int INF = 1e9;
const int MAXN = 1e5 + 5;
const ll LINF = 1e18;
const double pi = acos(-1);
const double EPS = 1e-9;
template <class T> using MinPQ = priority_queue<T, vector<T>, greater<T>>;
template <class T> using MaxPQ = priority_queue<T>;

int n;
ll k;
int a[MAXN];
vector< vector<int> > g;
bitset<MAXN> vis;

void bfs(int s) {
    queue<int> q; q.push(s);
    ll curSize = a[s];
    vis[s] = 1;
    while (!q.empty()) {
        int u = q.front(); q.pop();
        for (int& v : g[u]) {
            if (!vis[v] && (ll) a[v] + curSize <= k) {
                q.push(v);
                curSize += a[v];
                vis[v] = 1;
            }
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false); cin.tie(NULL);
    scanf("%d %lld", &n, &k);
    g.assign(n, vector<int>());
    for (int i = 0; i < n; i++) scanf("%d", a + i);
    for (int i = 0; i < n - 1; i++) {
        int x, y;
        scanf("%d %d", &x, &y); --x; --y;
        g[x].emplace_back(y);
        g[y].emplace_back(x);
    }
    int ans = 0;
    for (int i = 0; i < n; i++) {
        if ((int) g[i].size() == 1 && !vis[i]) {
            ans++;
            bfs(i);
        }
    }
    for (int i = 0; i < n; i++) {
        if (!vis[i]) {
            ans++;
            bfs(i);
        }
    }
    printf("%d\n", ans - 1);
    return 0;
}

Compilation message (stderr)

paprike.cpp: In function 'int main()':
paprike.cpp:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %lld", &n, &k);
     ~~~~~^~~~~~~~~~~~~~~~~~~
paprike.cpp:40:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for (int i = 0; i < n; i++) scanf("%d", a + i);
                                 ~~~~~^~~~~~~~~~~~~
paprike.cpp:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &x, &y); --x; --y;
         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 13 / 13
• Subtask 3: 0 / 27
• Subtask 4: 0 / 49