Submission #124149

#	Time	Username	Problem	Language	Result	Execution time	Memory
124149		Mtaylor	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	10 / 100	28 ms	23928 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){
      queue<pair<ll,ll> > pq;
		for(auto t:tab[u]){
			pq.push(mp(0,u*50000 + p[t]));
		}
		vis[u]=1;
      pair<ll,ll>  ras;
      while(!pq.empty()){
        ras=pq.front();
        pq.pop();
        ll x=ras.s/50000;
        ll y=ras.s%50000;
        if(x==b[1]){
          ans=max(ans,-ras.f);
          continue; 
        }
        ll z;
        //cout << x << " " << y << endl;
        if(vis[x]==0){
        for(auto t: tab[x]){
        	z=maa[x*50000+p[t]];
        	if(x+p[t]<n){
        		if(maa[(x+p[t])*50000+p[t]]==0){
        			pq.push(mp(ras.f-1,(x+p[t])*50000+p[t] ));
        			maa[(x+p[t])*50000+p[t]]=1;
        		}
        	}
        	if(x-p[t]>=0){
        		if(maa[(x-p[t])*50000+p[t]]==0){
        			pq.push(mp(ras.f-1,(x-p[t])*50000+p[t] ));
        			maa[(x-p[t])*50000+p[t]]=1;
        		}
        	}
        }
        vis[x]=1;
        }
        z=maa[50000*(x+y)+y];
        if(x+y <n && z==0){
        	maa[50000*(x+y)+y]=-ras.f+1;
        	if(x+y == b[1]){
        		ans=max(ans,-ras.f+1);
        		continue;
        	}
        	pq.push(mp(ras.f-1,50000*(x+y)+y));
        }
        z=maa[50000*(x-y)+y];
        if(x-y >=0 && z==0){
        	maa[50000*(x-y)+y]=-ras.f+1;
        	if(x-y == b[1]){
        		ans=max(ans,-ras.f+1);
        		continue;
        	}
        	pq.push(mp(ras.f-1,50000*(x-y)+y));
        }
        //cout << x << endl;
        
      }
    }
 
 
   
 
    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