Submission #525987

#	Time	Username	Problem	Language	Result	Execution time	Memory
525987		idas	Regions (IOI09_regions)	C++11	100 / 100	5630 ms	42072 KiB

regions

#include <bits/stdc++.h>
#define FAST_IO ios_base::sync_with_stdio(0); cin.tie(nullptr); cout.tie(nullptr)
#define FOR(i, begin, end) for(int i = (begin); i < (end); i++)
#define TSTS int ttt; cin >> ttt; while(ttt--) solve()
#define all(x) (x).begin(), (x).end()
#define le(vec) vec[vec.size()-1]
#define sz(x) ((int)((x).size()))
#define pb push_back
#define s second
#define f first

using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef map<int, int> mii;
typedef pair<int, int> pii;
typedef pair<long long, long long> pll;
typedef pair<long double, long double> pdd;

const int INF=1e9, MOD=1e9+7, mod=998244353;
const ll LINF=1e18;

void setIO()
{
    FAST_IO;
}

void setIO(string s)
{
    FAST_IO;
    freopen((s+".in").c_str(), "r", stdin);
    freopen((s+".out").c_str(), "w", stdout);
}

const int N=2e5+10, R=25010;
int n, r, q, t, rg[N], tin[N], tout[N], id;
ll pre[510][N], pref[N];
vi ad[N], gr[R], st[R];
set<int> big;
mii c;

void build(int u)
{
    tout[u]=tin[u]=++t;
    for(auto x : ad[u]){
        build(x);
        tout[u]=max(tout[u], tout[x]);
    }
}

int main()
{
    setIO();
    cin >> n >> r >> q;
    cin >> rg[0];
    gr[rg[0]].pb(0);
    FOR(i, 1, n)
    {
        int x; cin >> x;
        x--; cin >> rg[i];
        gr[rg[i]].pb(i);
        ad[x].pb(i);
    }
    build(0);

    int sq=sqrt(n);
    FOR(i, 1, r+1)
    {
        if(sz(gr[i])>sq){
            big.insert(i);
        }
    }
    for(auto x : big) c[x]=++id;

    for(auto x : big){
        FOR(i, 0, n+1) pref[i]=0;
        for(auto i : gr[x]){
            pref[tin[i]]++;
            pref[tout[i]+1]--;
        }
        FOR(i, 1, n+1) pref[i]+=pref[i-1];
        FOR(i, 1, r+1)
        {
            for(auto j : gr[i]){
                pre[c[x]][i]+=pref[tin[j]];
            }
        }
    }

    FOR(i, 1, r+1)
    {
        for(auto x : gr[i]){
            st[i].pb(tin[x]);
        }
        sort(all(st[i]));
    }

    while(q--){
        int r1, r2;
        cin >> r1 >> r2;
        if(!big.count(r1)){
            ll ans=0;
            for(auto i : gr[r1]){
                int le=-1, ri=sz(st[r2])-1;
                while(le<ri){
                    int m=(le+ri+1)/2;
                    if(st[r2][m]>tout[i]) ri=m-1;
                    else le=m;
                }

                int l0=0, r0=sz(st[r2]);
                while(l0<r0){
                    int m0=(l0+r0)/2;
                    if(st[r2][m0]<tin[i]) l0=m0+1;
                    else r0=m0;
                }

                if(le!=-1&&l0!=sz(st[r2])){
                    ans+=le-l0+1;
                }
            }
            cout << ans << endl;
        }
        else{
            cout << pre[c[r1]][r2] << endl;
        }
    }
}

Compilation message (stderr)

regions.cpp: In function 'void setIO(std::string)':
regions.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     freopen((s+".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen((s+".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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