C Messenger in MAC 

题目大意：

 

思路解析：

        答案计算为   , 可以发现当所选的几个信息固定后，其实后面的一项就变为b_max - b_min，得到了这个结论之后，其实我们可以直接把整个信息按照b进行排序，枚举l,r，那么我最多能选的信息的限制就变为了 a的和 <= L - (br -bl)，

因为我们需要选择最多的信息，所以我们在l-r中选择尽量a较小的信息。但是我们可以把选择较小，转为当我们在还能选择时就把当前的选择，当超过时，就不选择当前已经选择中最大的信息。

这部分代码：（这里set可以使用任意排序的数据结构） 每次选择的东西大于限制时，就弹出已经选择了的最大信息

代码实现：

import java.io.*;
import java.util.*;import static java.lang.String.*;public class Main {static int MAXN = 100005;static int n;static int mod = 1000000;static long INF = (long) 1e18;public static void main(String[] args) throws IOException {FastScanner f = new FastScanner();PrintWriter w = new PrintWriter(System.out);int t = f.nextInt();for (int o = 0; o < t; o++) {int n = f.nextInt();int l = f.nextInt();int[][]  a = new int[n][2];for (int i = 0; i < n; i++) {a[i][0] = f.nextInt();a[i][1] = f.nextInt();}Arrays.sort(a, ((o1, o2) -> {return o1[1] - o2[1];}));int max = 0;for (int i = 0; i < n; i++) {PriorityQueue<Integer> set = new PriorityQueue<>(new Comparator<Integer>() {@Overridepublic int compare(Integer o1, Integer o2) {return o2 - o1;}});long cur = 0;for (int j = i; j < n; j++) {if (a[j][1] - a[i][1] > l) break;cur += a[j][0];set.add(a[j][0]);while(a[j][1] - a[i][1] + cur > l){int num = set.poll();cur -= num;}max = Math.max(max, set.size());}}w.println(max);}w.flush();w.close();}private static class FastScanner {final private int BUFFER_SIZE = 1 << 16;private DataInputStream din;private byte[] buffer;private int bufferPointer, bytesRead;private FastScanner() throws IOException {din = new DataInputStream(System.in);buffer = new byte[BUFFER_SIZE];bufferPointer = bytesRead = 0;}private short nextShort() throws IOException {short ret = 0;byte c = read();while (c <= ' ') c = read();boolean neg = (c == '-');if (neg) c = read();do ret = (short) (ret * 10 + c - '0');while ((c = read()) >= '0' && c <= '9');if (neg) return (short) -ret;return ret;}private int nextInt() throws IOException {int ret = 0;byte c = read();while (c <= ' ') c = read();boolean neg = (c == '-');if (neg) c = read();do ret = ret * 10 + c - '0';while ((c = read()) >= '0' && c <= '9');if (neg) return -ret;return ret;}public long nextLong() throws IOException {long ret = 0;byte c = read();while (c <= ' ') c = read();boolean neg = (c == '-');if (neg) c = read();do ret = ret * 10 + c - '0';while ((c = read()) >= '0' && c <= '9');if (neg) return -ret;return ret;}private char nextChar() throws IOException {byte c = read();while (c <= ' ') c = read();return (char) c;}private String nextString() throws IOException {StringBuilder ret = new StringBuilder();byte c = read();while (c <= ' ') c = read();do {ret.append((char) c);} while ((c = read()) > ' ');return ret.toString();}private void fillBuffer() throws IOException {bytesRead = din.read(buffer, bufferPointer = 0, BUFFER_SIZE);if (bytesRead == -1) buffer[0] = -1;}private byte read() throws IOException {if (bufferPointer == bytesRead) fillBuffer();return buffer[bufferPointer++];}}}