제출 #124120

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
124120		Mtaylor	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	10 / 100	27 ms	24028 KiB

skyscraper

#include <bits/stdc++.h>
 
    using namespace std;
    typedef long long ll;
    typedef vector<ll> vl ;
 
    #define mp make_pair
    #define pb push_back
    #define f first
    #define s second
    #define all(v) (v).begin(),(v).end()
 
 
    const int MOD = 1000000007;
    const int N = 1000005;
    const double PI =4*atan(1);
    const double eps = 1e-7;
 
    ll n,m;
    ll x,y;
    vl tab[N];
    ll p[N];
    ll b[N];
    bool vis[N];
    unordered_map<ll ,ll> maa;
    ll ans=-1;
 
    void bfs(ll u){
      deque<pair<ll,ll> > pq;
		for(auto t:tab[u]){
			pq.push_back(mp(0,u*50000 + p[t]));
		}
		vis[u]=1;
      pair<ll,ll>  ras;
      while(!pq.empty()){
        ras=pq.front();
        pq.pop_front();
        ll x=ras.s/50000;
        ll y=ras.s%50000;
        if(x==b[1]){
          ans=max(ans,-ras.f);
          continue ;
        }
        //cout << x << " " << y << endl;
        ll z=maa[50000*(x+y)+y];
        if(x+y <n && (z==0 || (z!=0 && -ras.f+1<z))){
        	maa[50000*(x+y)+y]=-ras.f+1;
        	if(x+y == b[1]){
        		ans=max(ans,-ras.f+1);
        		continue;;
        	}
        	pq.push_back(mp(ras.f-1,50000*(x+y)+y));
        }
        z=maa[50000*(x-y)+y];
        if(x-y >=0 && (z==0 || (z!=0 && -ras.f+1<z))){
        	maa[50000*(x-y)+y]=-ras.f+1;
        	if(x-y == b[1]){
        		ans=max(ans,-ras.f+1);
        		continue;
        	}
        	pq.push_back(mp(ras.f-1,50000*(x-y)+y));
        }
        //cout << x << endl;
        if(vis[x])continue;
        for(auto t: tab[x]){
        	z=maa[x*50000+p[t]];
        	if(z==0 || (z!=0 && -ras.f+1 <z)){
        		pq.push_front(mp(ras.f,x*50000+p[t] ));
        		maa[x*50000+p[t]]=-ras.f+1;
        	}
        }
        vis[x]=1;
      }
    }
 
 
   
 
    int main(){
        ios::sync_with_stdio(0);
        //freopen("easy.txt","r",stdin);
        cin >> n >>m ;
        for(int i=0;i<m;i++){
          cin >> x >> y;
          p[i]=y;
          b[i]=x;
          tab[x].pb(i);
        }
        //cout << b[0]<< endl;
        bfs(b[0]);
        cout << ans;
 
 
 
 
        return 0;
    }

• Subtask 1: 10 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43