Submission #1107920

#	Time	Username	Problem	Language	Result	Execution time	Memory
1107920		koukirocks	File Paths (BOI15_fil)	C++17	100 / 100	416 ms	44852 KiB

fil

#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
 
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
 
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;

bool can(int v,int x,vvector<pll> &child,vector<int> &fa,vvector<ll> &cst,vector<ll> pval,int n,ll s,vector<pll> &did,vector<ll> &allp) {
    if (pval[v]==x) return true;
    {
        int now=v;
        while (now!=-1) {
            int val = x+pval[now]-pval[v]-s;
            auto it = lower_bound(all(allp),val);
            if (it!=allp.end() and *it==val) return true;
            now=fa[now];
        }
    }
    int tx=x-pval[v];
    vector<int> fac;
    for (int i=1;i<=sqrt(tx)+eps;i++) {
        if (tx%i==0) {
            fac.push_back(i);
            if (i*i!=tx) {
                fac.push_back(tx/i);
            }
        }
    }
    {
        int now=v;
        while (now!=-1) {
            for (int y:fac) {
                int val = pval[now]+tx/y-s;
                // cout<<now<<" "<<tx<<" "<<y<<" "<<s<<" "<<val<<" now tx y s val\n";
                auto it = lower_bound(all(cst[now]),val);
                if (it!=cst[now].end() and *it==val) return true;
            }
            now=fa[now];
        }
    }
    return false;
}

void dfs(int v,vector<pll> &did,vvector<pll> &child,int &tm,vvector<ll> &cst,vector<ll> &pval) {
    did[v].F=tm++;
    for (auto [i,l]:child[v]) {
        dfs(i,did,child,tm,cst,pval);
        for (ll j:cst[i]) cst[v].push_back(j);
    }
    cst[v].push_back(pval[v]);
    sort(all(cst[v]));
    did[v].S=tm++;
}

int main() {
    speed;
    ll n,m,k;
    cin>>n>>m>>k;
    ll s;
    cin>>s;
    s++;
    vvector<pll> child(n+1);
    vector<int> fa(n+1);
    vvector<ll> cst(n+1);
    vector<ll> pval(n+1);
    vector<ll> allp;
    fa[0]=-1;
    pval[0]=0;
    allp.push_back(0);
    for (int i=1;i<=n;i++) {
        ll p,l;
        cin>>p>>l;
        l++;
        child[p].emplace_back(i,l);
        fa[i]=p;
        pval[i]=pval[p]+l;
        allp.push_back(pval[i]);
    }
    sort(all(allp));
    // for (int i=0;i<=n;i++) {
    //     cout<<i<<" : ";
    //     for (int j:pre[i]) cout<<j<<" ";
    //     cout<<"\n";
    // }
    int tm=1;
    vector<pll> did(n+1);
    dfs(0,did,child,tm,cst,pval);
    while (m--) {
        int p,l;
        cin>>p>>l;
        l++;
        bool flag = can(p,k-l,child,fa,cst,pval,n,s,did,allp);
        if (flag) cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}

/*
2 1 40
9
0 1
1 5
1 1
*/

• Subtask 1: 33 / 33
• Subtask 2: 33 / 33
• Subtask 3: 34 / 34