Submission #392319

#	Time	Username	Problem	Language	Result	Execution time	Memory
392319		achibasadzishvili	Regions (IOI09_regions)	C++17	100 / 100	7306 ms	46576 KiB

regions

#include<bits/stdc++.h>
#define ll int
#define f first
#define s second
#define pb push_back
using namespace std;
const int N = 200005;
ll n,r,q,sq,pown = 1;
ll timer,in[N],out[N],cur,c[N],p[N],ch[N],ind[26000],b[N];
vector<ll>v[N],g[N];
int ans[805][26000],rev[805][26000];
void go(ll x){
    timer++;
    in[x] = timer;
    for(auto to : v[x]){
        go(to);
    }
    out[x] = timer;
}
void solve(ll x,ll y){
    cur += (c[x] == y);
    ch[x] = (c[x] == y);
    for(auto to : v[x]){
        solve(to , y);
        ch[x] += ch[to];
    }
    if(c[x] != y){
        rev[ind[y]][c[x]] += ch[x];
        ans[ind[y]][c[x]] += cur;
    }
    cur -= (c[x] == y);
}
void add(ll x,ll y){
    while(y<=n){
        b[y]+=x;
    	y+=y&-y;
    }
}
ll sum(ll y){
    ll x=0;
	while(y>0){
        x+=b[y];
        y-=y&-y;
    }
    return x;
}
int main(){
    cin >> n >> r >> q;
    sq = sqrt(n);
    vector<int>big;
    while(pown <= n)
        pown *= 2;
    cin >> c[1];
    g[c[1]].pb(1);
    for(int i=2; i<=n; i++){
        cin >> p[i] >> c[i];
        g[c[i]].pb(i);
        v[p[i]].pb(i);
    }
    
    go(1);
    for(int i=1; i<=r; i++){
        if(g[i].size() >= sq){
            big.pb(i);
            ind[i] = big.size();
        }
    }
    
    for(auto a : big){
        for(int i=1; i<=r; i++){
            ans[ind[a]][i] = 0;
            rev[ind[a]][i] = 0;
        }
        solve(1 , a);
    }
    ll x,y;
    while(q--){
        cin >> x >> y;
        if(g[x].size() >= sq){
            cout << ans[ind[x]][y] << endl;
            continue;
        }
        if(g[y].size() >= sq){
            cout << rev[ind[y]][x] << endl;
            continue;
        }
        for(auto a : g[y]){
            add(1 , in[a]);
        }
        ll ret = 0;
        for(auto a : g[x]){
            ret += sum(out[a]) - sum(in[a] - 1);
        }
        for(auto a : g[y]){
            add(-1 , in[a]);
        }
        cout << ret << endl;
    }
    
    
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:63:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   63 |         if(g[i].size() >= sq){
      |            ~~~~~~~~~~~~^~~~~
regions.cpp:79:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   79 |         if(g[x].size() >= sq){
      |            ~~~~~~~~~~~~^~~~~
regions.cpp:83:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   83 |         if(g[y].size() >= sq){
      |            ~~~~~~~~~~~~^~~~~

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