Submission #862008

#	Time	Username	Problem	Language	Result	Execution time	Memory
862008		lozergam	Regions (IOI09_regions)	C++14	0 / 100	139 ms	127520 KiB

regions

#include <bits/stdc++.h>
#include <numeric>
using namespace std;
#define ll int
#define pb push_back

ll min(ll a , ll b)
{
    if(a < b)return a;
    return b;
}

ll max(ll a , ll b)
{
    if(a > b)return a;
    return b;
}

const ll maxn = 200052, max_SQRT = 125; // la la lay lay
ll N, R, Q, H[maxn], rgnOrd[maxn >> 3], revOrd[maxn >> 3];
vector<ll> adj[maxn], rgnLst[maxn >> 3], rgnLst2[maxn >> 3];

ll timer, tin[maxn], tout[maxn];
ll tdall[max_SQRT][max_SQRT], td[maxn][max_SQRT];
void dfs(ll f)
{
    tin[f] = timer++;
    for (ll i = 0; i < min(R, max_SQRT) && revOrd[H[f]] < max_SQRT; i++)
    {
        tdall[revOrd[H[f]]][i] += td[f][i];
    }
    for (ll nf : adj[f])
    {
        for (ll i = 0; i < min(R, max_SQRT); i++)
        {
            td[nf][i] = td[f][i] + (rgnOrd[i] == H[f]);
        }
        dfs(nf);
    }
    tout[f] = timer - 1;
}

signed main()
{
    scanf("%d%d%d%d", &N, &R, &Q, &H[0]);
    rgnLst[--H[0]].push_back(0);
    for (ll i = 1, p; i < N; i++)
    {
        scanf("%d%d", &p, &H[i]);
        adj[--p].push_back(i);
        rgnLst[--H[i]].push_back(i);
    }

    iota(rgnOrd, rgnOrd + R, 0);
    sort(rgnOrd, rgnOrd + R, [&](const ll &a, const ll &b)
         { return rgnLst[a].size() > rgnLst[b].size(); });
    for (ll i = 0; i < R; i++)
    {
        revOrd[rgnOrd[i]] = i;
    }
    dfs(0);
    for (ll i = 0; i < R; i++)
    {
        for (ll j : rgnLst[i])
        {
            rgnLst2[i].push_back(tin[j]);
        }
        sort(rgnLst2[i].begin(), rgnLst2[i].end());
    }

    for (ll a, b, ans; Q--;)
    {
        scanf("%d%d", &a, &b);
        a--, b--;
        ans = 0;
        if (revOrd[a] < max_SQRT && revOrd[b] < max_SQRT)
        {
            ans = tdall[revOrd[b]][revOrd[a]];
        }
        else if (revOrd[a] < max_SQRT)
        {
            for (ll i : rgnLst[b])
            {
                ans += td[i][revOrd[a]];
            }
        }
        else
        {
            for (ll i : rgnLst[a])
            {
                ans += upper_bound(rgnLst2[b].begin(), rgnLst2[b].end(), tout[i]) - lower_bound(rgnLst2[b].begin(), rgnLst2[b].end(), tin[i]);
            }
        }
        printf("%d\n", ans);
    }
}
/*
 ZZZZZZZ     A        M     M     IIIIIII  N     N   TTTTTTTTTT  RRRRRR   EEEEEEE  EEEEEEE
      Z     A A      M M   M M       I     NN    N       TT      R     R  E        E
     Z     A   A    M   M M   M      I     N N   N       TT      R     R  E        E
    Z     AAAAAAA  M     M     M     I     N  N  N       TT      RRRRRR   EEEEEEE  EEEEEEE
   Z      A     A  M           M     I     N   N N       TT      RR       E        E
  Z       A     A  M           M     I     N    NN       TT      R R      E        E
 ZZZZZZZ  A     A  M           M  IIIIIII  N     N       TT      R  R     EEEEEEE  EEEEEEE
 */

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:45:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |     scanf("%d%d%d%d", &N, &R, &Q, &H[0]);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:49:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |         scanf("%d%d", &p, &H[i]);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~
regions.cpp:73:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         scanf("%d%d", &a, &b);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 85