Submission #872190

#	Time	Username	Problem	Language	Result	Execution time	Memory
872190		overwatch9	Regions (IOI09_regions)	C++17	55 / 100	8057 ms	56876 KiB

regions

#include <iostream>
#include <unordered_map>
#include <set>
#include <vector>
#include <algorithm>
using namespace std;
const int maxn = 2e5;
int visit[maxn], finish[maxn], region[maxn];
vector <int> adj[maxn];
vector <int> region_members[maxn];
int t = 0;
void dfs(int s, int p) {
    visit[s] = t++;
    region_members[region[s]].push_back(s);
    for (auto i : adj[s])
        dfs(i, s);
    finish[s] = t++;
}
bool is_ancestor(int a, int b) {
    return visit[a] <= visit[b] && finish[a] >= finish[b];
}
int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    int n, r, q;
    cin >> n >> r >> q;
    cin >> region[1];
    for (int i = 2; i <= n; i++) {
        int x;
        cin >> x;
        adj[x].push_back(i);
        cin >> region[i];
    }
    dfs(1, 1);
    while (q--) {
        int r1, r2;
        cin >> r1 >> r2;
        int ans = 0;
        vector <int> starts(region_members[r2].size());
        for (int j = 0; j < region_members[r2].size(); j++)
            starts[j] = visit[region_members[r2][j]];
        sort(starts.begin(), starts.end());
        for (int i = 0; i < region_members[r1].size(); i++) {
            auto l = upper_bound(starts.begin(), starts.end(), visit[region_members[r1][i]]);
            auto r = upper_bound(starts.begin(), starts.end(), finish[region_members[r1][i]]);
            if (r == starts.begin())
                continue;
            r--;
            int id1 = l - starts.begin();
            int id2 = r - starts.begin();
            ans += max(0, (id2 - id1 + 1));
        }
        cout << ans << endl;
    }
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:40:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   40 |         for (int j = 0; j < region_members[r2].size(); j++)
      |                         ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:43:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |         for (int i = 0; i < region_members[r1].size(); i++) {
      |                         ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 40 / 85