結果

問題 No.2316 Freight Train
ユーザー AsahiAsahi
提出日時 2023-05-26 22:42:50
言語 Java21
(openjdk 21)
結果
AC  
実行時間 375 ms / 2,000 ms
コード長 6,910 bytes
コンパイル時間 4,437 ms
コンパイル使用メモリ 79,968 KB
実行使用メモリ 51,356 KB
最終ジャッジ日時 2024-06-07 08:06:14
合計ジャッジ時間 13,931 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge3
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 49 ms
37,004 KB
testcase_01 AC 48 ms
36,936 KB
testcase_02 AC 49 ms
36,832 KB
testcase_03 AC 305 ms
44,932 KB
testcase_04 AC 208 ms
41,548 KB
testcase_05 AC 182 ms
41,452 KB
testcase_06 AC 129 ms
39,624 KB
testcase_07 AC 234 ms
40,768 KB
testcase_08 AC 249 ms
46,988 KB
testcase_09 AC 254 ms
43,388 KB
testcase_10 AC 234 ms
43,604 KB
testcase_11 AC 289 ms
48,216 KB
testcase_12 AC 272 ms
44,444 KB
testcase_13 AC 348 ms
50,956 KB
testcase_14 AC 331 ms
48,616 KB
testcase_15 AC 369 ms
50,820 KB
testcase_16 AC 332 ms
46,296 KB
testcase_17 AC 348 ms
48,764 KB
testcase_18 AC 375 ms
51,356 KB
testcase_19 AC 371 ms
50,796 KB
testcase_20 AC 347 ms
49,364 KB
testcase_21 AC 367 ms
51,160 KB
testcase_22 AC 348 ms
48,752 KB
testcase_23 AC 293 ms
48,636 KB
testcase_24 AC 317 ms
46,668 KB
testcase_25 AC 296 ms
49,252 KB
testcase_26 AC 293 ms
48,652 KB
testcase_27 AC 198 ms
40,800 KB
testcase_28 AC 49 ms
36,832 KB
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ソースコード

diff # 

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

class Main{
    void solve(PrintWriter out, In in) {        
        int n = in.nextInt() , Q = in.nextInt();
        int [] par = in.IntArray(n);
        DSU dsu = new DSU(n);
        for(int i = 0 ; i < n ; i ++ ) {
            if(par[i] == -1) continue;
            dsu.unite(i,par[i]-1);
        }
        while(Q-->0) {
            int a = in.nextInt() , b = in.nextInt();
            a--;b--;
            out.println(dsu.same(a,b)?"Yes":"No");
        }
    }   
    /* Library */   
    class DSU {
        private int[] rank;
        private int [] parent;
        private int [] size;
        DSU(int n) {
            this.parent = new int[n];
            this.rank = new int[n];
            this.size = new int[n];
            for (int i = 0 ; i < n; i ++ ) {
                parent[i] = i;
                rank[i] = 0;
                size[i] = 1;
            }
        }
        int groups() {
            int count = 0;
            for(int i = 0;i < parent.length ; i ++ ) {
                if(i == find(i)) {
                    count++;
                }
            }
            return count;
        }
        int size(int x){
            return size[find(x)];
        }
        int find(int x) {
            if (x == parent[x]) {
                return x;
            } else {
                parent[x] = find(parent[x]);
                return parent[x];
            }
        }
        boolean same(int x, int y) {
            return find(x) == find(y);
        }
        void unite(int x, int y) {
            int xRoot = find(x);
            int yRoot = find(y);
            if (xRoot == yRoot) {
                return;
            }
            if (rank[xRoot] > rank[yRoot]) {
                parent[yRoot] = xRoot;
            } else if (rank[xRoot] < rank[yRoot]) {
                parent[xRoot] = yRoot;
            } else {
                parent[xRoot] = yRoot;
                rank[xRoot]++;
                size[yRoot] += size[xRoot];
            }
        }
    }
    /* ------- */
    public static void main(String[] args) {
        PrintWriter out = new PrintWriter(System.out);
        In in  = new In();
        new Main().solve(out,in);
        out.flush();
    }
    /* Const */
    final long MOD7 = 1000000007; final long MOD9 = 998244353 ;
    final int [] X4 = {0,1,0,-1}; final int [] Y4 = {-1,0,1,0};
    final int [] X8 = {-1,-1,0,1,1,1,0,-1}; final int [] Y8 = {0,1,1,1,0,-1,-1,-1};
    final int Inf = (int)1e9; final long Lnf = (long)1e18;
    final String yes = "Yes"; final String no = "No";
    /* ----- */
}
/* Class */

/* ----- */
class Pair{
    private int first ;
    private int second;
    Pair(int first,int second) {
        this.first = first;
        this.second = second;
    }
    int first()  { return this.first ; }
    int second() { return this.second; }
    @Override
    public String toString(){ return first()+" = "+second(); }
}
class PairII {
    private int first ;
    private int second ;
    private int third;
    PairII(int first, int second, int third) {
        this.first = first;
        this.second = second;
        this.third = third;
    }
    int first()  { return this.first ; }
    int second() { return this.second; }
    int third()  { return this.third ; }
    @Override
    public String toString(){ return first()+" = "+second()+" = "+third() ; }
}
class In{
    private final InputStream in = System.in;
    private final byte[] buffer = new byte[1024];
    private int ptr = 0;
    private int buflen = 0;
    private boolean hasNextByte() {
        if (ptr < buflen) {
            return true;
        }else{
            ptr = 0;
            try {
                buflen = in.read(buffer);
            } catch (IOException e) {
                e.printStackTrace();
            }
            if (buflen <= 0) {
                return false;
            }
        }
        return true;
    }
    private int readByte() { 
        if (hasNextByte()) return buffer[ptr++]; else return -1;
    }
    private static boolean isPrintableChar(int c) { 
        return 33 <= c && c <= 126;
    }
    public boolean hasNext() { 
        while(hasNextByte() && !isPrintableChar(buffer[ptr])) {
            ptr++; 
        }
        return hasNextByte();
    }
    String next() {
        if (!hasNext()) throw new NoSuchElementException();
        StringBuilder sb = new StringBuilder();
        int b = readByte();
        while(isPrintableChar(b)) {
            sb.appendCodePoint(b);
            b = readByte();
        }
        return sb.toString();
    }

    long nextLong() {
        if (!hasNext()) throw new NoSuchElementException();
        long n = 0;
        boolean minus = false;
        int b = readByte();
        if (b == '-') {
            minus = true;
            b = readByte();
        }
        if (b < '0' || '9' < b) {
            throw new NumberFormatException();
        }
        while(true){
            if ('0' <= b && b <= '9') {
                n *= 10;
                n += b - '0';
            }else if(b == -1 || !isPrintableChar(b)){
                return minus ? -n : n;
            }else{
                throw new NumberFormatException();
            }
            b = readByte();
        }
    }
    int nextInt() {
        long nl = nextLong();
        if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
        return (int) nl;
    }
    double nextDouble() { 
        return Double.parseDouble(next());
    }
    int [] IntArray(int n) {
        final int [] Array = new int [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = nextInt();
        }
        return Array;
    }
    int [][] IntArray(int n , int m) {
        final int [][] Array = new int [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = IntArray(m);
        }
        return Array;
    }   
    long [] LongArray(int n) {
        final long [] Array = new long [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = nextLong();
        }
        return Array;
    }
    long [][] LongArray(int n , int m) {
        final long [][] Array = new long [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = LongArray(m);
        }
        return Array;
    }
    String [] StringArray(int n) {
        final String [] Array = new String [n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next();
        }
        return Array;
    }
    char [] CharArray(int n) {
        final char [] Array = new char[n];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next().charAt(0);
        }
        return Array;
    }
    char [][] CharArray(int n , int m) {
        final char [][] Array = new char [n][m];
        for(int i = 0 ; i < n ; i ++ ) {
            Array[i] = next().toCharArray();
        }
        return Array;
    }
}
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