Submission #1300814

#TimeUsernameProblemLanguageResultExecution timeMemory
1300814tolgaRegions (IOI09_regions)C++20
33 / 100
2425 ms32864 KiB
#include <iostream> #include <vector> #include <algorithm> typedef long long ll; const int maxn = 5 + 2e5, maxr = 25005; std::vector<int> edges[maxn]; int vert[maxn], tin[maxn], tout[maxn], calc[505][maxr], timer = 0; void dfs(int u) { tin[u] = ++timer; for (int v : edges[u]) dfs(v); tout[u] = timer; } int sum = 0; void heavy_dfs(int R, int u, int par, int sum) { calc[R][vert[u]] += sum; for (int v : edges[u]) heavy_dfs(R, v, u, sum + (vert[u] == R)); } int main() { std::ios::sync_with_stdio(false); std::cin.tie(nullptr), std::cout.tie(nullptr); int n, r, q; std::cin >> n >> r >> q; std::vector<std::vector<int>> reg(r + 1); std::cin >> vert[1]; reg[vert[1]].push_back(1); for (int i = 2; i <= n; i++) { int par; std::cin >> par >> vert[i]; reg[vert[i]].push_back(i); edges[par].push_back(i); } dfs(1); std::vector<std::vector<int>> reg_timer(r + 1); std::vector<int> heavy_idx(r + 1, -1); int idx = 0; for (int i = 1; i <= r; i++) { std::sort(reg[i].begin(), reg[i].end(), [](int &a, int &b) { return tin[a] < tin[b]; }); if (reg[i].size() * reg[i].size() > n) { heavy_idx[i] = ++idx; heavy_dfs(idx, 1, 0, (i == vert[1])); } reg_timer[i].reserve(reg[i].size()); for (int &v : reg[i]) reg_timer[i].push_back(tin[v]); } while (q--) { int r1, r2; std::cin >> r1 >> r2; if (heavy_idx[r1] != -1) { std::cout << calc[heavy_idx[r1]][r2] << std::endl; continue; } ll ans = 0; for (int &u : reg[r1]) { int left = std::lower_bound(reg_timer[r2].begin(), reg_timer[r2].end(), tin[u]) - reg_timer[r2].begin(); int right = std::upper_bound(reg_timer[r2].begin(), reg_timer[r2].end(), tout[u]) - reg_timer[r2].begin(); ans += right - left; } std::cout << ans << std::endl; } }
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