Submission #249465

#	Time	Username	Problem	Language	Result	Execution time	Memory
249465		AMO5	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	0 / 100	2 ms	1792 KiB

skyscraper

#include <bits/stdc++.h>

using namespace std;

#define fi first
#define se second
#define eb emplace_back
#define mt make_tuple
#define all(x) (x).begin(), (x).end() 
#define sz(x) int(x.size()) 
#define MOD 1000000007

typedef long long ll;
typedef pair <int, int> ii;
typedef pair <ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef long double ld;

const ll INF=LLONG_MAX;
const int mxn=3e5+5;
bool DEBUG=0;
int n,m,target;
int pos[mxn],jump[mxn];
map<int,int>mp;

struct doge{
	int cur;
	int cnt;
	bool vis[mxn];
	doge(int cur_, int cnt_, vector<bool>v){
		cur=cur_;
		cnt=cnt_;
		for(int i=0; i<sz(v); i++){
			vis[i]=v[i];
		}
	}
	bool operator < (const doge &rhs)const{
		return cnt>rhs.cnt;
	}
};

void solve(){
	priority_queue<doge>pq;
	vector<bool>vis(m);
	vis[0]=1;
	pq.push(doge(pos[0],0,vis));
	while(!pq.empty()){
		doge now = pq.top();
		pq.pop();
		int ind = mp[now.cur];
		int jmp = jump[ind];
		// to the left
		for(int cor = now.cur-jmp,cnt=1; cor>=0; cor-=jmp, cnt++){
			if(mp.count(cor)){
				int visit = mp[cor];
				if(visit==1){
					cout << cnt+now.cnt << endl;
					return;
				}
				if(!now.vis[visit]){
					doge nxt = now;
					nxt.cnt+=cnt;
					nxt.cur=cor;
					nxt.vis[visit]=1;
					pq.push(nxt);
				}
			}
		}
		// to the right
		for(int cor = now.cur+jmp,cnt=1; cor<n; cor+=jmp, cnt++){
			if(mp.count(cor)){
				int visit = mp[cor];
				if(visit==1){
					cout << cnt+now.cnt << endl;
					return;
				}
				if(!now.vis[visit]){
					doge nxt = now;
					nxt.cnt+=cnt;
					nxt.cur=cor;
					nxt.vis[visit]=1;
					pq.push(nxt);
				}
			}
		}
	}
	cout << -1 << endl;
	return;
}

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    //freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
	cin >> n >> m;
	for(int i=0; i<m; i++){
		cin >> pos[i] >> jump[i];
		mp[pos[i]]=i;
	}
	solve();
}
	
// READ & UNDERSTAND
// ll, int overflow, array bounds, memset(0)
// special cases (n=1?), n+1 (1-index)
// do smth instead of nothing & stay organized
// WRITE STUFF DOWN

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