Submission #74318

#	Time	Username	Problem	Language	Result	Execution time	Memory
74318		Bruteforceman	Regions (IOI09_regions)	C++11	100 / 100	6990 ms	75460 KiB

regions

#pragma GCC optimize("Ofast")
#include "bits/stdc++.h"
using namespace std;
int N, R, Q;
int a[200010], p[200010];
const int magic = 200;
const int chunk = 5 + (200000 / magic);
int ans[chunk][25001];
vector <int> g[200010];

int idx[25001];
int current;
int tot[25001];

void dfs(int x, int cnt) {
    cnt += (current == a[x]);
    if(a[x] != current) {
        ans[idx[current]][a[x]] += cnt;
    }
    for(auto i : g[x]) {
        dfs(i, cnt);
    }
} 

int in[200010];
int out[200010];
vector <int> v[25001];
vector <int> nodes[25001];
int cur;

void go(int x) {
    in[x] = ++cur;
    v[a[x]].emplace_back(in[x]);
    for(auto i : g[x]) {
        go(i);
    }
    out[x] = cur;
}
int count(int l, int r, int val) {
    return upper_bound(v[val].begin(), v[val].end(), r) - lower_bound(v[val].begin(), v[val].end(), l);
}

int main(int argc, char const *argv[])
{
    scanf("%d %d %d", &N, &R, &Q);
    for(int i = 1; i <= N; i++) {
        if(i == 1) scanf("%d", &a[i]);
        else scanf("%d %d", &p[i], &a[i]);
    }
    for(int i = 2; i <= N; i++) {
        g[p[i]].emplace_back(i);
    }
    for(int i = 1; i <= N; i++) {
        tot[a[i]] += 1;
        nodes[a[i]].emplace_back(i);
    }
    int now = 0;
    for(int i = 1; i <= R; i++) {
        if(tot[i] > magic) {
            current = i;
            idx[i] = now++; 
            dfs(1, 0);
        }
    }
    go(1);
    while(Q--) {
        int p, q;
        scanf("%d %d", &p, &q);
        if(tot[p] > magic) {
            printf("%d\n", ans[idx[p]][q]);
        } else {
            int res = 0;
            for(int i : nodes[p]) {
                res += count(in[i], out[i], q);
            }
            printf("%d\n", res);
        }
        fflush(stdout);
    }
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main(int, const char**)':
regions.cpp:45:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &N, &R, &Q);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:47:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         if(i == 1) scanf("%d", &a[i]);
                    ~~~~~^~~~~~~~~~~~~
regions.cpp:48:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         else scanf("%d %d", &p[i], &a[i]);
              ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:68:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &p, &q);
         ~~~~~^~~~~~~~~~~~~~~~~

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