Time Lapse :4min 2sec

1931.cpp

#include <iostream>
#include <memory.h>
#include <vector>
#include <algorithm>

using namespace std;

int N;
vector<pair<int, int>> list;
int main(void) {
    cin>>N;
    for(int i=0;i<N;i++)
    {
        int start, end;
        cin>>start>>end;
        list.push_back(make_pair(end,start));
    }
    sort(list.begin(),list.end());
    int cnt=1;
    int end = list[0].first;
    for(int i=1;i<list.size();i++)
    {
        if(list[i].second>=end)
        {
            end=list[i].first;
            cnt++;
        }
    }
    cout<<cnt<<endl;
}

1931.java

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Reader r = new Reader();
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));

        int n, ans = 1, e;
        meeting[] meetings = new meeting[n = r.nextInt()];
        for(int i = 0; i < n; ++i) {
            meetings[i] = new meeting(r.nextInt(), r.nextInt());
        }

        Arrays.sort(meetings, comparator);

        e = meetings[0].e;
        for(int i = 1; i < n; ++i) {
            if(meetings[i].s >= e) {
                e = meetings[i].e;
                ++ans;
            }
        }
        bw.write(ans + "");
        bw.flush();
    }

    static class meeting {
        public int s, e;
        public meeting(int s, int e) {
            this.s = s;
            this.e = e;
        }
    }

    static Comparator<meeting> comparator = new Comparator<meeting>() {
        @Override
        public int compare(meeting o1, meeting o2) {
            return o1.e == o2.e ? o1.s - o2.s : o1.e - o2.e;
        }
    };

    static class Reader {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

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

        public Reader(String file_name) throws IOException {
            din = new DataInputStream(new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException {
            byte[] buf = new byte[100001]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1) {
                if (c == '\n')
                    break;
                buf[cnt++] = (byte) c;
            }
            return new String(buf, 0, cnt);
        }

        public char nextchar() throws IOException {
            byte c = read();
            while (c <= ' ')
                c = read();

            return (char) c;
        }

        public int nextInt() throws IOException {
            int ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = (ret<<3) + (ret<<1)  + (c & 0b1111);
            } 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;
        }

        public double nextDouble() throws IOException {
            double ret = 0, div = 1;
            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 (c == '.') {
                while ((c = read()) >= '0' && c <= '9') {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        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++];
        }

        public void close() throws IOException {
            if (din == null)
                return;
            din.close();
        }
    }
}