#488178 (Java) No.1065 電柱 / Pole (Easy)

• 問題: No.1065 電柱 / Pole (Easy)
• ユーザー: uwi
• 提出日時: 2020-05-29 21:26:52
• 言語: Java (openjdk 23)
• 結果: AC
• 実行時間: 691 ms / 2,000 ms
• コード長: 6,482 bytes
• コンパイル時間: 4,248 ms
• コンパイル使用メモリ: 83,944 KB
• 実行使用メモリ: 85,444 KB
• 最終ジャッジ日時: 2024-11-06 02:27:49
• 合計ジャッジ時間: 24,427 ms
• ジャッジサーバーID （参考情報）: judge4 / judge5

ファイルパターン	結果
sample	AC * 2
other	AC * 46

ソースコード

package contest200529;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;

public class C {
	InputStream is;
	PrintWriter out;
	String INPUT = "";
	
	void solve()
	{
		int n = ni(), m = ni();
		int X = ni()-1, Y = ni()-1;
		int[][] co = new int[n][];
		for(int i = 0;i < n;i++){
			co[i] = na(2);
		}
		int[] from= new int[m];
		int[] to = new int[m];
		int[] ws = new int[m];
		for(int i = 0;i < m;i++){
			from[i] = ni()-1;
			to[i] = ni()-1;
			ws[i] = (int)d2(co[from[i]], co[to[i]]);
		}
		
		int[][][] g = packWU(n, from, to, ws);
		double[] ds = dijkl(g, X);
		out.printf("%.14f\n", ds[Y]);
	}
	
	public static double[] dijkl(int[][][] g, int from)
	{
		int n = g.length;
		double[] td = new double[n];
		
		Arrays.fill(td, Long.MAX_VALUE / 2);
		MinHeapD q = new MinHeapD(n);
		q.add(from, 0);
		td[from] = 0;
		
		while(q.size() > 0){
			int cur = q.argmin();
			q.remove(cur);
			
			for(int[] e : g[cur]){
				int next = e[0];
				double nd = td[cur] + Math.sqrt(e[1]);
				if(nd < td[next]){
					td[next] = nd;
					q.update(next, nd);
				}
			}
		}
		
		return td;
	}

	public static class MinHeapD {
		public double[] a;
		public int[] map;
		public int[] imap;
		public int n;
		public int pos;
		public static double INF = Double.POSITIVE_INFINITY;
		
		public MinHeapD(int m)
		{
			n = Integer.highestOneBit((m+1)<<1);
			a = new double[n];
			map = new int[n];
			imap = new int[n];
			Arrays.fill(a, INF);
			Arrays.fill(map, -1);
			Arrays.fill(imap, -1);
			pos = 1;
		}
		
		public double add(int ind, double x)
		{
			int ret = imap[ind];
			if(imap[ind] < 0){
				a[pos] = x; map[pos] = ind; imap[ind] = pos;
				pos++;
				up(pos-1);
			}
			return ret != -1 ? a[ret] : x;
		}
		
		public double update(int ind, double x)
		{
			int ret = imap[ind];
			if(imap[ind] < 0){
				a[pos] = x; map[pos] = ind; imap[ind] = pos;
				pos++;
				up(pos-1);
			}else{
				a[ret] = x;
				up(ret);
				down(ret);
			}
			return x;
		}
		
		public double remove(int ind)
		{
			if(pos == 1)return INF;
			if(imap[ind] == -1)return INF;
			
			pos--;
			int rem = imap[ind];
			double ret = a[rem];
			map[rem] = map[pos];
			imap[map[pos]] = rem;
			imap[ind] = -1;
			a[rem] = a[pos];
			a[pos] = INF;
			map[pos] = -1;
			
			up(rem);
			down(rem);
			return ret;
		}
		
		public double min() { return a[1]; }
		public int argmin() { return map[1]; }
		public int size() {	return pos-1; }
		
		private void up(int cur)
		{
			for(int c = cur, p = c>>>1;p >= 1 && a[p] > a[c];c>>>=1, p>>>=1){
				double d = a[p]; a[p] = a[c]; a[c] = d;
				int e = imap[map[p]]; imap[map[p]] = imap[map[c]]; imap[map[c]] = e;
				e = map[p]; map[p] = map[c]; map[c] = e;
			}
		}
		
		private void down(int cur)
		{
			for(int c = cur;2*c < pos;){
				int b = a[2*c] < a[2*c+1] ? 2*c : 2*c+1;
				if(a[b] < a[c]){
					double d = a[c]; a[c] = a[b]; a[b] = d;
					int e = imap[map[c]]; imap[map[c]] = imap[map[b]]; imap[map[b]] = e;
					e = map[c]; map[c] = map[b]; map[b] = e;
					c = b;
				}else{
					break;
				}
			}
		}
	}
	
	public static int[][][] packWU(int n, int[] from, int[] to, int[] w) {
		int[][][] g = new int[n][][];
		int[] p = new int[n];
		for (int f : from)
			p[f]++;
		for (int t : to)
			p[t]++;
		for (int i = 0; i < n; i++)
			g[i] = new int[p[i]][2];
		for (int i = 0; i < from.length; i++) {
			--p[from[i]];
			g[from[i]][p[from[i]]][0] = to[i];
			g[from[i]][p[from[i]]][1] = w[i];
			--p[to[i]];
			g[to[i]][p[to[i]]][0] = from[i];
			g[to[i]][p[to[i]]][1] = w[i];
		}
		return g;
	}

	
	public static long d2(int[] a, int[] b) { return (long)(b[0]-a[0])*(b[0]-a[0])+(long)(b[1]-a[1])*(b[1]-a[1]); }

	
	void run() throws Exception
	{
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		long s = System.currentTimeMillis();
		solve();
		out.flush();
		if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//		Thread t = new Thread(null, null, "~", Runtime.getRuntime().maxMemory()){
//			@Override
//			public void run() {
//				long s = System.currentTimeMillis();
//				solve();
//				out.flush();
//				if(!INPUT.isEmpty())tr(System.currentTimeMillis()-s+"ms");
//			}
//		};
//		t.start();
//		t.join();
	}
	
	public static void main(String[] args) throws Exception { new C().run(); }
	
	private byte[] inbuf = new byte[1024];
	public int lenbuf = 0, ptrbuf = 0;
	
	private int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
	private int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private double nd() { return Double.parseDouble(ns()); }
	private char nc() { return (char)skip(); }
	
	private String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){ // when nextLine, (isSpaceChar(b) && b != ' ')
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private long[] nal(int n)
	{
		long[] a = new long[n];
		for(int i = 0;i < n;i++)a[i] = nl();
		return a;
	}
	
	private char[][] nm(int n, int m) {
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private int[][] nmi(int n, int m) {
		int[][] map = new int[n][];
		for(int i = 0;i < n;i++)map[i] = na(m);
		return map;
	}
	
	private int ni() { return (int)nl(); }
	
	private long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { System.out.println(Arrays.deepToString(o)); }
}