Submission #1024893

#	Time	Username	Problem	Language	Result	Execution time	Memory
1024893		overwatch9	Stranded Far From Home (BOI22_island)	C++17	0 / 100	193 ms	11604 KiB

island

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 2e5 + 1;
ll S[maxn];
vector <int> adj[maxn];
bool ans[maxn];
ll sz[maxn];
void dfs(int s, int p) {
    sz[s] = S[s];
    for (auto i : adj[s]) {
        if (i == p)
            continue;
        dfs(i, s);
        sz[s] += sz[i];
    }
}
vector <int> v;
void dfs2(int s, int p) {
    for (auto i : adj[s]) {
        if (i == p)
            continue;
        dfs2(i, s);
    }
    if (sz[s] >= S[p])
        v.push_back(s);
    else
        v.clear();
    if (p == 1) {
        if (sz[s] >= S[1]) {
            for (auto j : v)
                ans[j] = true;
        }
    }
}
int main() {
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++)
        cin >> S[i];
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    dfs(1, 1);
    for (auto i : adj[1]) {
        dfs2(i, 1);
      	v.clear();
    }
    ans[1] = 1;
    for (int i = 1; i <= n; i++)
        cout << ans[i];
    cout << '\n';
}

Compilation message (stderr)

island.cpp: In function 'int main()':
island.cpp:37:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |     freopen("in.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
island.cpp:38:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |     freopen("out.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 35