1028 List Sorting

Excel can sort records according to any column. Now you are supposed to imitate this function.

Input Specification:

Each input file contains one test case. For each case, the first line contains two integers N (≤105) and C, where N is the number of records and C is the column that you are supposed to sort the records with. Then N lines follow, each contains a record of a student. A student's record consists of his or her distinct ID (a 6-digit number), name (a string with no more than 8 characters without space), and grade (an integer between 0 and 100, inclusive).

Output Specification:

For each test case, output the sorting result in N lines. That is, if C = 1 then the records must be sorted in increasing order according to ID's; if C = 2 then the records must be sorted in non-decreasing order according to names; and if C = 3 then the records must be sorted in non-decreasing order according to grades. If there are several students who have the same name or grade, they must be sorted according to their ID's in increasing order.

Sample Input 1:

3 1
000007 James 85
000010 Amy 90
000001 Zoe 60

Sample Output 1:

000001 Zoe 60
000007 James 85
000010 Amy 90

Sample Input 2:

4 2
000007 James 85
000010 Amy 90
000001 Zoe 60
000002 James 98

Sample Output 2:

000010 Amy 90
000002 James 98
000007 James 85
000001 Zoe 60

Sample Input 3:

4 3
000007 James 85
000010 Amy 90
000001 Zoe 60
000002 James 9

Sample Output 3:

000002 James 9
000001 Zoe 60
000007 James 85
000010 Amy 90

#include <iostream>
#include <algorithm>
using namespace std;

struct Stu {
	string id;
	string name;
	int grade;
} a[100010];

bool cmp1(Stu s1, Stu s2) {
	return s1.id < s2.id;
}

bool cmp2(Stu s1, Stu s2) {
	return s1.name == s2.name ? s1.id < s2.id : s1.name < s2.name;
}

bool cmp3(Stu s1, Stu s2) {
	return s1.grade == s2.grade ? s1.id < s2.id : s1.grade < s2.grade;
}

int main() {
	int n, c;
	cin >> n >> c;
	for (int i = 0; i < n; i++) {
		cin >> a[i].id >> a[i].name >> a[i].grade;
	}
	if (c == 1) {
		sort(a, a + n, cmp1);
	} else if (c == 2) {
		sort(a, a + n, cmp2);
	} else if (c == 3) {
		sort(a, a + n, cmp3);
	}
	for (int i = 0; i < n; i++) {
		cout << a[i].id << ' ' << a[i].name << ' ' << a[i].grade << endl;
	}
	return 0;
}