Submission #1083093

#	Time	Username	Problem	Language	Result	Execution time	Memory
1083093		_8_8_	Railway (BOI17_railway)	C++17	100 / 100	210 ms	124500 KiB

railway

#include <bits/stdc++.h>

using namespace std;
    
typedef long long ll;
const int  N = 1e6 + 12, MOD = (int)1e9 + 7;

int n, s[N], m, k, res[N], val[N];
vector<pair<int,int>> g[N];
vector<int> c[N];
map<int,int> col[N];


void dfs(int v, int pr = -1, int pid = 0) {
    int f = 0;
    for(auto [to,i]:g[v]) {
        if(to == pr) continue;
        dfs(to, v, i);
        if((int)col[to].size() > (int)col[v].size()) {
            swap(f,res[i]);
            col[to].swap(col[v]);
        }
        for(auto [x,y]:col[to]) {
            if(!col[v].count(x)) {
                f++;
            }
            col[v][x] += y;
            if(col[v][x] == s[x]) {
                f--;
            }
        }
    }
    for(auto j:c[v]) {
        col[v][j]++;
        if(col[v][j] == 1) {
            f++;
        }
        if(col[v][j] == s[j]) {
            f--;
        }
    }
    val[pid] = res[pid] = f;
}
void test() {
    cin >> n >> m >> k;
    for(int i = 1; i <= n - 1; i++) {
        int a, b;
        cin >> a >> b;
        g[a].push_back({b,i});
        g[b].push_back({a,i});
    }
    for(int i = 1; i <= m; i++) {
        cin >> s[i];
        for(int j = 0; j < s[i]; j++) {
            int x;
            cin >> x;
            if((int)c[x].size() && c[x].back() == i) continue;
            c[x].push_back(i);
        }
    }
    dfs(1);
    vector<int> ans;
    for(int i = 1; i <= n - 1; i++) {
        // cout << i << ' ' << res[i] << '\n';
        if(val[i] >= k) {
            ans.push_back(i);
        }
    }
    cout << (int)ans.size() << '\n';
    for(auto i:ans) {
        cout << i << ' ';
    }
}
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int t = 1; 
    // cin >> t;
    while(t--) 
        test();

    return 0;
}       

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 7 / 7
• Subtask 4: 29 / 29
• Subtask 5: 16 / 16
• Subtask 6: 25 / 25