1006 sign in and sign out (25 points) (PAT class a)

Problem Description:

At the beginning of every day, the first person who signs in the computer room will unlock the door, and the last one who signs out will lock the door. Given the records of signing in's and out's, you are supposed to find the ones who have unlocked and locked the door on that day.

Input Specification:

Each input file contains one test case. Each case contains the records for one day. The case starts with a positive integer M, which is the total number of records, followed by M lines, each in the format:

ID_number Sign_in_time Sign_out_time

where times are given in the format HH:MM:SS, and ID_number is a string with no more than 15 characters.

Output Specification:

For each test case, output in one line the ID numbers of the persons who have unlocked and locked the door on that day. The two ID numbers must be separated by one space.

Note: It is guaranteed that the records are consistent. That is, the sign in time must be earlier than the sign out time for each person, and there are no two persons sign in or out at the same moment.

Sample Input:

3
CS301111 15:30:28 17:00:10
SC3021234 08:00:00 11:25:25
CS301133 21:45:00 21:58:40

Sample Output

SC3021234 CS301133

The main idea of the topic ： Here you are. n Time for individuals to enter and leave the room , Let you find the number of the first person to enter and the last person to leave . A stupid way is used here , But fortunately, it's solved .

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#include <iostream>
#include <algorithm>
using namespace std;
struct p{
	char id[20];
	char bt[20];
	char et[20];
};
bool cmp1(struct p a, struct p b) {
	int h1, m1, s1;
	int h2, m2, s2;
	h1 = h2 = m1 = m2 = s1 = s2 = 0;
	for(int i = 0; i <= 1; i++) {
		h1 = h1*10 + (a.bt[i]-'0');
		h2 = h2*10 + (b.bt[i]-'0');
	}
	for(int i = 3; i <= 4; i++) {
		m1 = m1*10 + (a.bt[i]-'0');
		m2 = m2*10 + (b.bt[i]-'0');
	}
	for(int i = 6; i <= 7; i++) {
		s1 = s1*10 + (a.bt[i]-'0');
		s2 = s2*10 + (b.bt[i]-'0');
	}
	if(h1 != h2) {
		return h1 < h2;
	} else {
		if(m1 != m2) {
			return m1 < m2;
		} else {
			return s1 < s2;
		}
	}
}
bool cmp2(struct p a, struct p b) {
	int h1, m1, s1;
	int h2, m2, s2;
	h1 = h2 = m1 = m2 = s1 = s2 = 0;
	for(int i = 0; i <= 1; i++) {
		h1 = h1*10 + (a.et[i]-'0');
		h2 = h2*10 + (b.et[i]-'0');
	}
	for(int i = 3; i <= 4; i++) {
		m1 = m1*10 + (a.et[i]-'0');
		m2 = m2*10 + (b.et[i]-'0');
	}
	for(int i = 6; i <= 7; i++) {
		s1 = s1*10 + (a.et[i]-'0');
		s2 = s2*10 + (b.et[i]-'0');
	}
	if(h1 != h2) {
		return h1 > h2;
	} else {
		if(m1 != m2) {
			return m1 > m2;
		} else {
			return s1 > s2;
		}
	}
}
int main() {
	int t;
	struct p a[1010];
	scanf("%d", &t);
	for(int i = 0; i < t; i++) {
		scanf("%s%s%s", a[i].id, a[i].bt, a[i].et);
	}
	sort(a, a+t, cmp1);
	printf("%s ", a[0].id);
	sort(a, a+t, cmp2);
	printf("%s\n", a[0].id);
	return 0;
}

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