Submission #116486

#	Time	Username	Problem	Language	Result	Execution time	Memory
116486		roseanne_pcy	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	57 / 100	1081 ms	104124 KiB

skyscraper

#include <bits/stdc++.h>
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
using namespace std;
#define X first
#define Y second
#define pb push_back
typedef pair<int, int> ii;
typedef long long ll;
 
const int maxn = 3e4+5;
const int half = 173;
 
int n, m;
int dist[maxn];
set<int> unvis[180][180];
vector<int> png[maxn];
 
bool good(int x)
{
	return 0<= x && x< n;
}
 
void bfs(int s)
{
	for(int i = 0; i< n; i++) dist[i] = 1e9;
	priority_queue<pair<int, int> > pq;
	pq.push(ii(0, s)); dist[s] = 0;
	while(!pq.empty())
	{
		auto kk = pq.top(); pq.pop();
		int u = kk.Y, d = -kk.X;
		for(int i = 1; i<= half; i++) unvis[i][u%i].erase(u);
		if(d> dist[u]) continue;
		for(int pw : png[u])
		{
			if(pw> half)
			{
				int cur = u;
				int w = 1;
				while(cur< n)
				{
					int nxt = cur+pw;
					if(good(nxt) && dist[nxt]> w+dist[u]) 
					{
						dist[nxt] = w+dist[u];
						// for(int i = 1; i<= half; i++) unvis[i][nxt%i].erase(nxt);
						pq.push(ii(-dist[nxt], nxt));
					}
					w++;
					cur = nxt;
				}
				cur = u;
				w = 1;
				while(cur>= 0)
				{
					int nxt = cur-pw;
					if(good(nxt) && dist[nxt]> w+dist[u])
					{
						dist[nxt] = w+dist[u];
						// for(int i = 1; i<= half; i++) unvis[i][nxt%i].erase(nxt);
						pq.push(ii(-dist[nxt], nxt));
					}
					cur = nxt;
					w++;
				}
			}
			else
			{
				for(int nxt : unvis[pw][u%pw])
				{
					// if(u == 4) printf("go %d\n", nxt);
					if(dist[nxt]> abs(u-nxt)/pw+dist[u])
					{
						dist[nxt] = abs(u-nxt)/pw+dist[u];
						// for(int i = 1; i<= half; i++) unvis[i][nxt%i].erase(nxt);
						pq.push(ii(-dist[nxt], nxt));
					}
				}
				unvis[pw][u%pw].clear();
			}
		}
	}
}
 
int hom[maxn], mana[maxn];
 
int main()
{
	scanf("%d %d", &n, &m);
	for(int i = 0; i< m; i++)
	{
		scanf("%d %d", &hom[i], &mana[i]);
		png[hom[i]].pb(mana[i]);
	}
	for(int md = 1; md<= half; md++)
	{
		for(int i = 0; i< n; i++)
		{
			unvis[md][i%md].insert(i);
		}
	}
	// printf("okay\n");
	bfs(hom[0]);
	if(dist[hom[1]] == 1e9) printf("-1\n");
	else printf("%d\n", dist[hom[1]]);
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:90:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:93:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d", &hom[i], &mana[i]);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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