Submission #537839

#	Time	Username	Problem	Language	Result	Execution time	Memory
537839		Gurban	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	755 ms	28224 KiB

skyscraper

#include "bits/stdc++.h"
using namespace std;

using ll = long long;

const int maxn=3e4+5;
const int B = 192;
int n,m,st,fn;
int b[maxn],p[maxn];
int dis[maxn * B];
bool vis[maxn * B],done[maxn];
vector<int>doge[maxn];

int main(){
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> n >> m;
	int sq = sqrt(n)+1;
	for(int i = 0;i < m;i++){
		cin >> b[i] >> p[i];
		if(i == 0) st = b[i];
		if(i == 1) fn = b[i];
		doge[b[i]].push_back(p[i]);
	}

	for(int i = 0;i < n * sq;i++) dis[i] = 1e9;

	dis[st * sq] = 0;
	priority_queue<pair<int,int>>q;
	q.push({0,st * sq});
	while(!q.empty()){
		int x = q.top().second;
		q.pop();
		if(vis[x]) continue;
		vis[x] = 1;
		
		int bb = x / sq;
		int pw = x % sq;

		// cout<<bb<<' '<<pw<<'\n';

		if(!pw){
			for(auto i : doge[bb]){
				if(i < sq){
					int to = bb * sq + i;
					if(dis[to] > dis[x]){
						dis[to] = dis[x];
						q.push({-dis[to],to});
					}
				}
				else {
					for(int j = 1;;j++){
						int to = bb - i * j;
						if(to < 0) break;
						if(dis[to * sq] > dis[x] + j){
							dis[to * sq] = dis[x] + j;
							q.push({-dis[to * sq],to * sq});
						}
					}
					for(int j = 1;;j++){
						int to = bb + i * j;
						if(to >= n) break;
						if(dis[to * sq] > dis[x] + j){
							dis[to * sq] = dis[x] + j;
							q.push({-dis[to * sq],to * sq});
						}
					}
				}
			}
		}
		else {
			if(dis[bb * sq] > dis[x]){
				dis[bb * sq] = dis[x];
				q.push({-dis[bb*sq],bb*sq});
			}

			if(bb - pw >= 0 and dis[(bb - pw) * sq + pw] > dis[x] + 1){
				dis[(bb - pw) * sq + pw] = dis[x] + 1;
				q.push({-dis[(bb - pw) * sq + pw],(bb - pw) * sq + pw});
			}
			if(bb + pw < n and dis[(bb + pw) * sq + pw] > dis[x] + 1){
				dis[(bb + pw) * sq + pw] = dis[x] + 1;
				q.push({-dis[(bb + pw) * sq + pw],(bb + pw) * sq + pw});
			}	
		}
	}

	if(dis[fn * sq] == 1e9) cout<<-1;
	else cout<<dis[fn * sq];
}

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