#576715 (Java) No.1282 Display Elements

• 問題: No.1282 Display Elements
• ユーザー: ywmt
• 提出日時: 2020-11-06 22:18:43
• 言語: Java (openjdk 23)
• 結果: AC
• 実行時間: 337 ms / 2,000 ms
• コード長: 6,307 bytes
• コンパイル時間: 2,409 ms
• コンパイル使用メモリ: 78,468 KB
• 実行使用メモリ: 47,332 KB
• 最終ジャッジ日時: 2024-07-22 13:04:38
• 合計ジャッジ時間: 6,832 ms
• ジャッジサーバーID （参考情報）: judge2 / judge3

ファイルパターン	結果
other	AC * 24

ソースコード

import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.NoSuchElementException;

public class Main {
    static PrintWriter out;
    static InputReader ir;

    static void solve() {
        int n = ir.nextInt();
        int[] a = ir.nextIntArray(n);
        int[] b = ir.nextIntArray(n);
        Arrays.sort(a);
        int[] c = new int[2 * n];
        for (int i = 0; i < n; i++) {
            c[i] = a[i];
            c[i + n] = b[i];
        }
        c = compress(c);
        long res = 0;
        BinaryIndexedTree bit = new BinaryIndexedTree(500000);
        for (int i = 0; i < n; i++) {
            bit.update(c[i + n], 1);
            res += bit.sum(c[i]);
        }
        out.println(res);
    }

    public static int[] compress(int[] a) {
        int n = a.length;
        int[] r = a.clone();
        Arrays.sort(r);
        int[] ret = new int[n];
        for (int i = 0; i < n; i++)
            ret[i] = lower_bound(r, 0, n - 1, a[i]);
        return ret;
    }

    public static int lower_bound(int[] a, int fromIndex, int toIndex, int val) {
        if (val > a[toIndex])
            return toIndex + 1;
        if (val <= a[fromIndex])
            return fromIndex;
        int lb = fromIndex - 1, ub = toIndex;
        while (ub - lb > 1) {
            int mid = (ub - lb) / 2 + lb;
            if (a[mid] >= val) {
                ub = mid;
            } else {
                lb = mid;
            }
        }
        return ub;
    }

    static class BinaryIndexedTree {
        // 0-indexed
        private long[] bit;
        private int SIZE;

        public BinaryIndexedTree(int n) {
            bit = new long[n + 1];
            SIZE = n;
        }

        // sum of segment[0,i)
        public long sum(int i) {
            long res = 0;
            while (i > 0) {
                res += bit[i];
                i -= i & -i;
            }
            return res;
        }

        // sum of segment[start,end)
        public long sum(int start, int end) {
            return sum(end) - sum(start);
        }

        public long get(int i) {
            return sum(i + 1) - sum(i);
        }

        public void update(int i, long x) {
            i++;
            while (i <= SIZE) {
                bit[i] += x;
                i += i & -i;
            }
        }

        public int size() {
            return SIZE;
        }
    }

    public static void main(String[] args) {
        ir = new InputReader(System.in);
        out = new PrintWriter(System.out);
        solve();
        out.flush();
    }

    static class InputReader {

        private InputStream in;
        private byte[] buffer = new byte[1024];
        private int curbuf;
        private int lenbuf;

        public InputReader(InputStream in) {
            this.in = in;
            this.curbuf = this.lenbuf = 0;
        }

        public boolean hasNextByte() {
            if (curbuf >= lenbuf) {
                curbuf = 0;
                try {
                    lenbuf = in.read(buffer);
                } catch (IOException e) {
                    throw new InputMismatchException();
                }
                if (lenbuf <= 0)
                    return false;
            }
            return true;
        }

        private int readByte() {
            if (hasNextByte())
                return buffer[curbuf++];
            else
                return -1;
        }

        private boolean isSpaceChar(int c) {
            return !(c >= 33 && c <= 126);
        }

        private void skip() {
            while (hasNextByte() && isSpaceChar(buffer[curbuf]))
                curbuf++;
        }

        public boolean hasNext() {
            skip();
            return hasNextByte();
        }

        public String next() {
            if (!hasNext())
                throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while (!isSpaceChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }

        public int nextInt() {
            if (!hasNext())
                throw new NoSuchElementException();
            int c = readByte();
            while (isSpaceChar(c))
                c = readByte();
            boolean minus = false;
            if (c == '-') {
                minus = true;
                c = readByte();
            }
            int res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res = res * 10 + c - '0';
                c = readByte();
            } while (!isSpaceChar(c));
            return (minus) ? -res : res;
        }

        public long nextLong() {
            if (!hasNext())
                throw new NoSuchElementException();
            int c = readByte();
            while (isSpaceChar(c))
                c = readByte();
            boolean minus = false;
            if (c == '-') {
                minus = true;
                c = readByte();
            }
            long res = 0;
            do {
                if (c < '0' || c > '9')
                    throw new InputMismatchException();
                res = res * 10 + c - '0';
                c = readByte();
            } while (!isSpaceChar(c));
            return (minus) ? -res : res;
        }

        public double nextDouble() {
            return Double.parseDouble(next());
        }

        public int[] nextIntArray(int n) {
            int[] a = new int[n];
            for (int i = 0; i < n; i++)
                a[i] = nextInt();
            return a;
        }

        public long[] nextLongArray(int n) {
            long[] a = new long[n];
            for (int i = 0; i < n; i++)
                a[i] = nextLong();
            return a;
        }

        public char[][] nextCharMap(int n, int m) {
            char[][] map = new char[n][m];
            for (int i = 0; i < n; i++)
                map[i] = next().toCharArray();
            return map;
        }
    }

    static void tr(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
}