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package class020;
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import java.util.Arrays;
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import java.util.Comparator;
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import java.util.PriorityQueue;
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public class Code04_CoverMax {
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public static int maxCover1(int[][] lines) {
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int min = Integer.MAX_VALUE;
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int max = Integer.MIN_VALUE;
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for (int i = 0; i < lines.length; i++) {
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min = Math.min(min, lines[i][0]);
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max = Math.max(max, lines[i][1]);
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}
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int cover = 0;
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for (double p = min + 0.5; p < max; p += 1) {
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int cur = 0;
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for (int i = 0; i < lines.length; i++) {
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if (lines[i][0] < p && lines[i][1] > p) {
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cur++;
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}
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}
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cover = Math.max(cover, cur);
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}
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return cover;
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}
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public static int maxCover2(int[][] m) {
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Line[] lines = new Line[m.length];
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for (int i = 0; i < m.length; i++) {
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lines[i] = new Line(m[i][0], m[i][1]);
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}
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Arrays.sort(lines, new StartComparator());
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// lines
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//
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PriorityQueue<Integer> heap = new PriorityQueue<>();
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int max = 0;
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for (int i = 0; i < lines.length; i++) {
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// lines[i] -> cur 在黑盒中，把<=cur.start 东西都弹出
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while (!heap.isEmpty() && heap.peek() <= lines[i].start) {
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heap.poll();
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}
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heap.add(lines[i].end);
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max = Math.max(max, heap.size());
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}
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return max;
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}
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public static class Line {
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public int start;
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public int end;
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public Line(int s, int e) {
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start = s;
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end = e;
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}
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}
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public static class EndComparator implements Comparator<Line> {
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@Override
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public int compare(Line o1, Line o2) {
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return o1.end - o2.end;
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}
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}
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// for test
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public static int[][] generateLines(int N, int L, int R) {
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int size = (int) (Math.random() * N) + 1;
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int[][] ans = new int[size][2];
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for (int i = 0; i < size; i++) {
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int a = L + (int) (Math.random() * (R - L + 1));
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int b = L + (int) (Math.random() * (R - L + 1));
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if (a == b) {
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b = a + 1;
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}
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ans[i][0] = Math.min(a, b);
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ans[i][1] = Math.max(a, b);
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}
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return ans;
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}
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public static class StartComparator implements Comparator<Line> {
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@Override
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public int compare(Line o1, Line o2) {
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return o1.start - o2.start;
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}
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}
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public static void main(String[] args) {
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Line l1 = new Line(4, 9);
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Line l2 = new Line(1, 4);
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Line l3 = new Line(7, 15);
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Line l4 = new Line(2, 4);
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Line l5 = new Line(4, 6);
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Line l6 = new Line(3, 7);
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// 底层堆结构，heap
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PriorityQueue<Line> heap = new PriorityQueue<>(new StartComparator());
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heap.add(l1);
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heap.add(l2);
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heap.add(l3);
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heap.add(l4);
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heap.add(l5);
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heap.add(l6);
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while (!heap.isEmpty()) {
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Line cur = heap.poll();
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System.out.println(cur.start + "," + cur.end);
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}
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System.out.println("test begin");
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int N = 100;
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int L = 0;
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int R = 200;
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int testTimes = 200000;
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for (int i = 0; i < testTimes; i++) {
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int[][] lines = generateLines(N, L, R);
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int ans1 = maxCover1(lines);
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int ans2 = maxCover2(lines);
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if (ans1 != ans2) {
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System.out.println("Oops!");
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}
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}
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System.out.println("test end");
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}
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}
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