結果

問題 No.3200 Sinking Islands
コンテスト
ユーザー tenten
提出日時 2025-08-07 13:17:39
言語 Java
(openjdk 23)
結果
AC  
実行時間 504 ms / 2,000 ms
コード長 5,008 bytes
コンパイル時間 4,314 ms
コンパイル使用メモリ 88,940 KB
実行使用メモリ 68,484 KB
最終ジャッジ日時 2025-08-07 13:17:57
合計ジャッジ時間 15,502 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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ファイルパターン 結果
sample AC * 2
other AC * 20
権限があれば一括ダウンロードができます

ソースコード

diff # 

import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;
import java.math.*;

public class Main {
    public static void main(String[] args) throws Exception {
        FastScanner sc = new FastScanner();
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] lefts = new int[m];
        int[] rights = new int[m];
        for (int i = 0; i < m; i++) {
            lefts[i] = sc.nextInt() - 1;
            rights[i] = sc.nextInt() - 1;
        }
        int q = sc.nextInt();
        int[] events = new int[q];
        boolean[] brokens = new boolean[m];
        for (int i = 0; i < q; i++) {
            events[i] = sc.nextInt() - 1;
            brokens[events[i]] = true;
        }
        UnionFindTree uft = new UnionFindTree(n);
        for (int i = 0; i < m; i++) {
            if (!brokens[i]) {
                uft.unite(lefts[i], rights[i]);
            }
        }
        long current = (n - 1L) * n / 2;
        for (int i = 0; i < n; i++) {
            if (i == uft.find(i)) {
                current -= (uft.getCount(i) - 1L) * uft.getCount(i) / 2;
            }
        }
        long[] ans = new long[q];
        for (int i = q - 1; i >= 0; i--) {
            ans[i] = current;
            if (!uft.same(lefts[events[i]], rights[events[i]])) {
                current -= (long)uft.getCount(lefts[events[i]]) * uft.getCount(rights[events[i]]);
                uft.unite(lefts[events[i]], rights[events[i]]);
            }
        }
        System.out.println(Arrays.stream(ans).mapToObj(String::valueOf).collect(Collectors.joining("\n")));
    }
    
    static class UnionFindTree {
        int[] parents;
        int[] counts;
        
        public UnionFindTree(int size) {
            parents = IntStream.range(0, size).toArray();
            counts = new int[size];
            Arrays.fill(counts, 1);
        }
        
        public int find(int x) {
            return x == parents[x] ? x : (parents[x] = find(parents[x]));
        }
        
        public boolean same(int x, int y) {
            return find(x) == find(y);
        }
        
        public void unite(int x, int y) {
            int xx = find(x);
            int yy = find(y);
            if (xx != yy) {
                parents[xx] = yy;
                counts[yy] += counts[xx];
            }
        }
        
        public int getCount(int x) {
            return counts[find(x)];
        }
    }
}

class FastScanner {
    private DataInputStream din;
    private byte[] buffer;
    private int bufferPointer, bytesRead;
    private static final int BUFFER_SIZE = 1 << 16; // 65,536 バイト

    public FastScanner() {
        din = new DataInputStream(System.in);
        buffer = new byte[BUFFER_SIZE];
        bufferPointer = bytesRead = 0;
    }

    private byte read() {
        try {
            if (bufferPointer == bytesRead) {
                bytesRead = din.read(buffer, 0, BUFFER_SIZE);
                if (bytesRead == -1) return -1;
                bufferPointer = 0;
            }
            return buffer[bufferPointer++];
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String next() {
        byte b = read();
        // 空白文字を読み飛ばす
        while (isSpaceChar(b)) {
            b = read();
        }
        StringBuilder sb = new StringBuilder();
        while (!isSpaceChar(b)) {
            sb.append((char) b);
            b = read();
        }
        return sb.toString();
    }

    public int nextInt() {
        int ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public long nextLong() {
        long ret = 0;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10L + c - '0';
            c = read();
        } while (!isSpaceChar(c));
        return neg ? -ret : ret;
    }

    public double nextDouble() {
        double ret = 0, div = 1;
        byte c = read();
        while (isSpaceChar(c)) c = read();
        boolean neg = (c == '-');
        if (neg) c = read();
        do {
            ret = ret * 10 + c - '0';
            c = read();
        } while (!isSpaceChar(c) && c != '.');
        if (c == '.') {
            while (!isSpaceChar(c = read())) {
                ret += (c - '0') / (div *= 10);
            }
        }
        return neg ? -ret : ret;
    }

    private boolean isSpaceChar(byte c) {
        return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
    }

    public void close() {
        try {
            if (din != null) din.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}
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