Submission #450426

#	Time	Username	Problem	Language	Result	Execution time	Memory
450426		soba	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	57 / 100	1094 ms	153640 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;
const int N = 30001;
int dist[N];
vector<pair<int,int> >v[N];
int b[N] , p[N] ;
vector<pair<int,int> >vp;
int n , m ;

struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}

	size_t operator()(pair<uint64_t,uint64_t> x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x.first + FIXED_RANDOM)^(splitmix64(x.second + FIXED_RANDOM) >> 1);
	}
};
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int x , y;
    cin>> n>> m ;
    unordered_map< pair<int, int> , int , custom_hash> mp;
    for(int i = 0 ; i < m ; i++)
    {
        cin >> b[i] >> p[i];
        if(i==0)x=b[i];
        if(i==1)y=b[i];
        mp[{b[i],p[i]}]++;
        if(mp[{b[i],p[i]}]>1)continue;
        vp.push_back({b[i], p[i]});
    }
    if(x==y)
    {
        cout << 0 ;
        return 0;
    }
    sort(vp.begin(),vp.end());
    m=vp.size();
    for(int i = 0 ; i < m ; i++)
    {
        int c=1;
        for(int j = vp[i].first+vp[i].second ; j< n ; j+= vp[i].second)
        {
            v[vp[i].first].push_back({j , c});
            c++;
            if(mp[{j,vp[i].second}])
                break;
        }
    }
    for(int i = m-1 ; i >=0 ; i--)
    {
        int c=1;
        for(int j = vp[i].first-vp[i].second ; j>=0 ; j-= vp[i].second)
        {
            v[vp[i].first].push_back({j , c});
            c++;
            if(mp[{j,vp[i].second}])
                break;
        }
    }
    priority_queue<pair<int,int> >q;
    for (int i = 0; i <= n; i++) dist[i] = 1e9;
    dist[x] = 0;
    q.push({0,x});
    while (!q.empty())
    {
        int a = q.top().second;
        int ot= q.top().first;
        q.pop();
        if(0-ot > dist[a])continue;
        if(a==y)
        {
            cout << 0-ot;
            return 0;
        }

        //cout << a << " : " ;
        for (auto u : v[a])
        {
            int b = u.first, w = u.second;

          //  cout << b << " ";
            if (dist[a]+w < dist[b])
            {
                dist[b] = dist[a]+w;
                q.push({-dist[b],b});
            }
        }
        //cout << "\n";
    }
    cout << -1;

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:73:13: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   73 |     dist[x] = 0;
      |     ~~~~~~~~^~~
skyscraper.cpp:81:9: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   81 |         if(a==y)
      |         ^~

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