Submission #116503

#	Time	Username	Problem	Language	Result	Execution time	Memory
116503		roseanne_pcy	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	0 / 100	230 ms	254172 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*180*2];

vector<int> adj[maxn*180*2];
 
bool ok(int x)
{
	return 0<= x && x< n;
}

int N;

void bfs(int s)
{
	for(int i = 0; i< N+10; i++) dist[i] = 1e9;
	queue<int> q;
	dist[s] = 0; q.push(s);
	while(!q.empty())
	{
		int u = q.front(); q.pop();
		for(int v : adj[u])
		{
			if(dist[v]> dist[u]+1)
			{
				dist[v] = dist[u]+1;
				q.push(v);
			}
		}
	}
}
 
int hom[maxn], mana[maxn];
 
int conv(int u, int md, int isleft)
{
	if(isleft) return (half+1)*n+(md-1)*n+u;
	return md*n+u;
}
int main()
{
	scanf("%d %d", &n, &m);
	// printf("%d %d\n", conv(0, 1, 0), conv(0, 1, 1));
	for(int i = 0; i< m; i++)
	{
		scanf("%d %d", &hom[i], &mana[i]);
	}
	// printf("okay\n");
	for(int i = 0; i< n; i++)
	{
		for(int md = 1; md<= half; md++)
		{
			if(ok(i+md))
			{
				adj[conv(i, md, 0)].pb(i+md);
				adj[conv(i, md, 0)].pb(conv(i+md, md, 0));
			}
			if(ok(i-md))
			{
				adj[conv(i, md, 1)].pb(i-md);
				adj[conv(i, md, 1)].pb(conv(i-md, md, 1));
			}
		}
	}
	for(int i = 0; i< m; i++)
	{
		int pw = mana[i];
		if(pw> half)
		{
			int cur = hom[i];
			while(cur< n)
			{
				int nxt = cur+pw;
				if(ok(nxt)) adj[cur].pb(nxt);
				cur = nxt;
			}
			cur = hom[i];
			while(cur>= 0)
			{
				int nxt = cur-pw;
				if(ok(nxt)) adj[cur].pb(nxt);
				cur = nxt;
			}
		}
		else
		{
			int x = hom[i];
			if(ok(x-pw))
			{
				adj[x].pb(conv(x-pw, pw, 1));
				adj[x].pb(x-pw);
			}
			if(ok(x+pw))
			{
				adj[x].pb(conv(x+pw, pw, 0));
				adj[x].pb(x+pw);
			}
		}
	}
	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:54:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:58:8: 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: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43