Submission #682621

#	Time	Username	Problem	Language	Result	Execution time	Memory
682621		BhavayGoyal	Firefighting (NOI20_firefighting)	C++14	100 / 100	331 ms	41292 KiB

Firefighting

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

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<class T> using oset = 
            tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define int long long
#define ld long double
#define ar array
#define vi vector<int>
#define vii vector<vector<int>>
#define pii pair<int, int>
#define pb push_back
#define all(x) x.begin(), x.end()
#define f first
#define s second
#define endl "\n"

const int MOD = 1e9+7;
const int inf = 1e9;
const int linf = 1e18;

const int d4i[4]={-1, 0, 1, 0}, d4j[4]={0, 1, 0, -1};
const int d8i[8]={-1, -1, 0, 1, 1, 1, 0, -1}, d8j[8]={0, 1, 1, 1, 0, -1, -1, -1};


// -------------------------------------------------- Main Code --------------------------------------------------

const int N = 3e5+5;
int n, k, isUsed[N];
vi ans;
vector<pii> g[N];

int dfs(int src, int par, int lastWt) {
    int req = 0, ext = linf;
    for (auto child : g[src]) {
        int ch = child.f, wt = child.s;
        if (ch == par) continue;
        int x = dfs(ch, src, wt);
        if (!isUsed[ch]) req = max(req, x);
        else ext = min(ext, x);
    }

    if (ext+req <= k) {
        isUsed[src] = true;
        return lastWt+ext;
    }

    if (lastWt+req <= k) {
        return lastWt+req;
    }

    ans.pb(src);
    isUsed[src] = true;
    return lastWt;

    // have to add fire station on this node
}

void sol() {
    cin >> n >> k;
    for (int i = 0; i < n-1; i++) {
        int a, b, c; cin >> a >> b >> c;
        --a; --b;
        g[a].pb({b, c});
        g[b].pb({a, c});
    }

    dfs(0, -1, linf);
    cout << ans.size() << endl;
    reverse(all(ans));
    for (auto i : ans) cout << i+1 << " "; cout << endl;
}

signed main () {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int t = 1;
    // cin >> t; 
    while (t--) {
        sol();
    }
    return 0;
}

Compilation message (stderr)

Firefighting.cpp: In function 'void sol()':
Firefighting.cpp:76:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   76 |     for (auto i : ans) cout << i+1 << " "; cout << endl;
      |     ^~~
Firefighting.cpp:76:44: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   76 |     for (auto i : ans) cout << i+1 << " "; cout << endl;
      |                                            ^~~~

• Subtask 1: 3 / 3
• Subtask 2: 5 / 5
• Subtask 3: 9 / 9
• Subtask 4: 19 / 19
• Subtask 5: 26 / 26
• Subtask 6: 38 / 38