编程之美－－区间重合判断

import java.util.ArrayList;import java.util.Arrays;import java.util.Comparator;import java.util.List;import java.util.Scanner;public class SectionCoincide {    static class Line {int x, y;public Line(int x, int y) {    this.x = x;    this.y = y;}boolean isInclude(Line line) {    return x <= line.x && y >= line.y;}// 排序后使用，前提是 line 在this的右边public boolean join(Line line) {    if (y < line.x)return false;    y = line.y;    return true;}public String toString() {    return "[" + x + "," + y + "]";}    }    /**     * 将其以 x 排序，并合成不相交的 然后用二分查找在这些不相交的 line 中查找看是否有一个能完全覆盖目标     */    public static void execute(Line[] lines, Line target) {Arrays.sort(lines, new Comparator<Line>() {    @Override    public int compare(Line o1, Line o2) {return o1.x < o1.x ? -1 : (o1.x > o2.x ? 1 : 0);    }});List<Line> list = new ArrayList<Line>();list.add(lines[0]);int pos = 0;for (int i = 1, len = lines.length; i < len; i++) {    if (!list.get(pos).join(lines[i])) {list.add(lines[i]);pos++;    }}// 利用 二分查找在 list 中找出，将target.x,target.y 找出在哪一个区间，看它们是否同一区间System.out.println(list + " " + target);int a = getIndex(list, target.x);int b = getIndex(list, target.y);System.out.println(a == b ? "Yes" : "No");    }    static int getIndex(List<Line> list, int k) {int from = 0, to = list.size() - 1;while (from <= to) {    int mid = (from + to) >> 1;    if (k >= list.get(mid).x && k <= list.get(mid).y)return mid;    else if (k < list.get(mid).x)to = mid - 1;    elsefrom = mid + 1;}return -1;    }    static final int SIZE = 10;    public static void main(String args[]) {Scanner cin = new Scanner(SectionCoincide.class.getResourceAsStream("Line.txt"));int g = cin.nextInt();while (g-- > 0) {    int n = cin.nextInt();    Line[] lines = new Line[n];    for (int i = 0; i < n; i++) {int x = cin.nextInt();int y = cin.nextInt();lines[i] = new Line(x, y);    }    int targetx = cin.nextInt();    int targety = cin.nextInt();    Line target = new Line(targetx, targety);    execute(lines, target);}    }}