結果

問題 No.583 鉄道同好会
ユーザー yuya178yuya178
提出日時 2017-10-27 23:28:42
言語 Java21
(openjdk 21)
結果
AC  
実行時間 104 ms / 2,000 ms
コード長 5,510 bytes
コンパイル時間 2,604 ms
コンパイル使用メモリ 80,380 KB
実行使用メモリ 51,528 KB
最終ジャッジ日時 2024-11-21 23:24:32
合計ジャッジ時間 4,673 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge4
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 54 ms
50,092 KB
testcase_01 AC 55 ms
49,864 KB
testcase_02 AC 54 ms
50,060 KB
testcase_03 AC 53 ms
50,120 KB
testcase_04 AC 52 ms
50,172 KB
testcase_05 AC 53 ms
49,968 KB
testcase_06 AC 54 ms
49,848 KB
testcase_07 AC 56 ms
50,112 KB
testcase_08 AC 54 ms
50,116 KB
testcase_09 AC 54 ms
49,920 KB
testcase_10 AC 55 ms
50,096 KB
testcase_11 AC 82 ms
50,968 KB
testcase_12 AC 89 ms
51,528 KB
testcase_13 AC 78 ms
51,324 KB
testcase_14 AC 89 ms
51,484 KB
testcase_15 AC 92 ms
51,144 KB
testcase_16 AC 93 ms
51,260 KB
testcase_17 AC 104 ms
51,224 KB
testcase_18 AC 93 ms
51,468 KB
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ソースコード

diff # 

import java.io.*;
import java.util.*;

public class Main {
    InputStream is;
    PrintWriter out;
    String INPUT = "";

    int MOD = 1000000007;
    int INF = 10000000;

    void solve()
    {
        int n = ni();
        int m = ni();
        int[] a = new int[n];
        UnionFind uf = new UnionFind(n);
        for(int i = 0; i < m; i++){
            int b = ni();
            int c = ni();
            uf.union(b,c);
            a[b]++;
            a[c]++;
        }
        int prev = -1;
        for(int i = 0; i < n; i++){
            if(a[i]==0) continue;
            if(prev==-1){
                prev = uf.find(i);
                continue;
            }
            if(a[i]>0){
                int d = uf.find(i);
                if(d != prev){
                    out.println("NO");
                    return;
                }
                prev = d;
            }
        }
        int odd = 0;
        for(int i = 0; i < n; i++){
            if(a[i]%2==1) odd++;
        }
        if(odd == 0 || odd == 2){
            out.println("YES");
        }
        else out.println("NO");

    }

    public static class UnionFind{  
        int parent[];
        int rank[];
        
        public UnionFind(int n){
            parent = new int[n];
            rank   = new int[n];
            
            for(int i = 0;i < n;i++){
                parent[i] = i;
                rank[i]   = 0;
            }        
        }
        
        boolean same(int x,int y){
            return find(x) == find(y);
        }
        
        public int find(int x){
            if(parent[x] == x){
               return x;
            }else{
               return parent[x] = find(parent[x]);   
            }        
        }
          
        public void union(int x,int y){
            x = find(x);
            y = find(y);
            
            if(x != y){
                if(rank[x] > rank[y]){
                   parent[y] = x; 
                }else{
                   parent[x] = y;
                   if(rank[x] == rank[y]){
                       rank[y]++;
                   }
                }            
            }
            
            return;
        }
        
        public int count(int n){
            int ret = 0;
            for(int i = 0;i < n;i++){
                if(i == find(i)){
                    ret++;
                }
            }
            return ret;
        }
          
      } 

    

    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");
    }
    
    public static void main(String[] args) throws Exception { new Main().run(); }
    
    private byte[] inbuf = new byte[1024];
    private 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) && 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 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[] na(int n)
    {
        int[] a = new int[n];
        for(int i = 0;i < n;i++)a[i] = ni();
        return a;
    }
    
    private int ni()
    {
        int num = 0, 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 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)); }
}
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