Submission #696456

#	Time	Username	Problem	Language	Result	Execution time	Memory
696456		Cross_Ratio	Through Another Maze Darkly (CCO21_day1problem3)	C++14	0 / 25	29 ms	41384 KiB

Main

#include <bits/stdc++.h>
#define int long long
using namespace std;
vector<int> adj[800005];
int num[800005];
struct SegTree {
    vector<int> seg;
    int MAX;
    SegTree(int N) {
        int i;
        for(i=1;i<2*N;i*=2) {}
        seg.resize(i);
        MAX = i;
    }
    void Edit(int n, int a) {
        n += MAX/2;
        seg[n] += a;
        n /= 2;
        while(n) {
            seg[n] = seg[2*n] + seg[2*n+1];
            n /= 2;
        }
    }
    int kth(int k, int n, int ns, int ne) {
        if(ns+1==ne) return ns;
        int mid = ns + ne >> 1;
        if(k < seg[2*n]) return kth(k, 2*n, ns, mid);
        else return kth(k-seg[2*n], 2*n+1, mid, ne);
    }
};
int ans[800005];
int dfs_cnt = 0;
int A[1600005];
int lev[1600005];
vector<array<int, 2>> V;
void dfs(int c, int p, int d) {
    if(p != -1) V.push_back({c, d});
    int sz = adj[c].size();
    int i, j;
    if(p == -1) {
        for(i=1;i<sz;i++) {
            dfs(adj[c][i], c, d);
            V.push_back({c, d});
        }
        dfs(adj[c][0], c, d);
        V.push_back({c, d});
        return;
    }
    int pt = -1;
    for(i=0;i<sz;i++) {
        if(adj[c][i] == p) pt = i;
    }
    assert(pt != -1);
    for(i=pt+1;i<sz;i++) {
        dfs(adj[c][i], c, d+1);
        V.push_back({c, d+1});
    }
    if(pt != 0) {
        dfs(adj[c][0], c, d+1);
        V.push_back({c, d+1});
        for(i=1;i<pt;i++) {
            dfs(adj[c][i], c, d);
            V.push_back({c, d});
        }
    }
}
vector<int> B[800005];
vector<array<int, 2>> Query;
signed main() {
    cin.sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int N, Q;
    cin >> N >> Q;
    int i, j;
    for(i=0;i<N;i++) {
        int k;
        cin >> k;
        for(j=0;j<k;j++) {
            int c;
            cin >> c;
            adj[i].push_back(c-1);
        }
        num[i] = 1 % k;
    }
    dfs(0, -1, 1);
    //cout << "dfs done\n";
    int sz = V.size();
    SegTree tree(sz+3);
    int MAX = tree.MAX;
    int ma = 0;
    for(i=0;i<sz;i++) {
        A[i] = V[i][0];
        ma = max(ma, V[i][1]);
        B[V[i][1]].push_back(i);
    }
    for(i=0;i<Q;i++) {
        int a;
        cin >> a;
        Query.push_back({a-1, i});
    }
    sort(Query.begin(),Query.end());
    int sum = 0;
    int cnt = 0;
    int qt = 0;
    //cout << "Start Finding\n";
    //for(i=0;i<sz;i++) cout << A[i] << ' ';
    //cout << '\n';
    for(i=1;i<=ma;i++) {
        for(int n : B[i]) {
            tree.Edit(n, 1);
            //cout << n << ' ';
            sum++;
        }
        //cout << '\n';
        //cout<< i << ":\n";
        while(qt<Query.size()&&Query[qt][0] < cnt + sum) {
            //cout << qt << " : ";
            int v = Query[qt][0] - cnt;
            //cout << v << ' ';
            //cout << tree.kth(v, 1, 0, MAX/2) << '\n';
            ans[Query[qt][1]] = A[tree.kth(v, 1, 0, MAX/2)];
            qt++;
        }
        //cout << '\n';
        cnt += sum;
    }
    while(qt < Query.size()) {
        int v = (Query[qt][0] - cnt) % sum;
        ans[Query[qt][1]] = A[tree.kth(v, 1, 0, MAX/2)];
        qt++;
    }
    for(i=0;i<Q;i++) cout << ans[i]+1 << '\n';
}

Compilation message (stderr)

Main.cpp: In member function 'long long int SegTree::kth(long long int, long long int, long long int, long long int)':
Main.cpp:26:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   26 |         int mid = ns + ne >> 1;
      |                   ~~~^~~~
Main.cpp: In function 'void dfs(long long int, long long int, long long int)':
Main.cpp:39:12: warning: unused variable 'j' [-Wunused-variable]
   39 |     int i, j;
      |            ^
Main.cpp: In function 'int main()':
Main.cpp:117:17: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |         while(qt<Query.size()&&Query[qt][0] < cnt + sum) {
      |               ~~^~~~~~~~~~~~~
Main.cpp:128:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::array<long long int, 2> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  128 |     while(qt < Query.size()) {
      |           ~~~^~~~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 0 / 4
• Subtask 3: 0 / 12
• Subtask 4: 0 / 5