Coding/F_Tree_TREE.cpp at main · nishantlamba29/Coding · GitHub

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

const int N = 2e5 + 5;
vector<int> adj[N];
int sz[N];
int dp[N];

void dfs(int node, int p, int k) {
    sz[node] = 1;
    dp[node] = 0;
    for(auto &j : adj[node]) if(j != p) {
        dfs(j, node, k);
        sz[node] += sz[j];
        dp[node] += dp[j];
    }
    if(sz[node] >= k) dp[node] += 1;
}

void dfs2(int node, int p, int k, int &ans) {
    ans += dp[node];
    for(auto &j : adj[node]) if(j != p) {

        bool p_sz = (sz[j] >= k);
        bool n_sz = (sz[node] - sz[j] >= k);

        sz[j] = sz[node];
        dp[j] = dp[node] - p_sz + n_sz;

        dfs2(j, node, k, ans);
    }
}

void solve() {

    int n, k;
    cin >> n >> k;
    for(int i=0;i<=n;i++) {
        dp[i] = 0;
        adj[i].clear();
    }

    for(int i=0;i<n-1;i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    dfs(1, -1, k);
    int ans = 0;
    dfs2(1, -1, k, ans);

    cout << ans << "\n";

}


int32_t main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int _;
    cin >> _;
    while (_-->0) {
        solve();
    }

    return 0;
}