Submission #116512

#	Time	Username	Problem	Language	Result	Execution time	Memory
116512		roseanne_pcy	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	22 / 100	462 ms	262144 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< ii > 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; i++) dist[i] = 1e9;
	priority_queue< pair<int, int> > q;
	dist[s] = 0; q.push({0, s});
	while(!q.empty())
	{
		auto kk = q.top(); q.pop();
		int u = kk.Y, d = -kk.X;
		if(d> dist[u]) continue;
		for(auto k2 : adj[u])
		{
			int v = k2.X, w = k2.Y;
			// printf("(%d, %d)\n", v, w);
			if(dist[v]> dist[u]+w)
			{
				dist[v] = dist[u]+w;
				q.push({-dist[v], 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);
	N = conv(n-1, half, 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, 1});
				adj[conv(i, md, 0)].pb({conv(i+md, md, 0), 1});
			}
			if(ok(i-md))
			{
				adj[conv(i, md, 1)].pb({i-md, 1});
				adj[conv(i, md, 1)].pb({conv(i-md, md, 1), 1});
			}
		}
	}
	for(int i = 0; i< m; i++)
	{
		int pw = mana[i];
		if(pw> half)
		{
			int cur = hom[i]+pw;
			while(cur< n)
			{
				adj[hom[i]].pb({cur, abs(cur-hom[i])/pw});
				cur += pw;
			}
			cur = hom[i]-pw;
			while(cur>= 0)
			{
				adj[hom[i]].pb({cur, abs(cur-hom[i])/pw});
				cur -= pw;
			}
		}
		else
		{
			int x = hom[i];
			adj[x].pb({conv(x, pw, 0), 0});
			adj[x].pb({conv(x, pw, 1), 0});
		}
	}
	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:58:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
  ~~~~~^~~~~~~~~~~~~~~~~
skyscraper.cpp:62:8: 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: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43