[C/C++] 1028 List Sorting (25 分)

1028 List Sorting (25 分)

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 (≤10^​5 ) 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 90

Sample Output 3:

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

---

可以写多个cmp，根据不同的情况，选用不同的cmp

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;

struct record{
	int id;
	char name[10];
	int grade;
}stu[100010];

bool cmp1(record a, record b)
{
	return a.id < b.id;
}
bool cmp2(record a, record b)
{
	if( strcmp(a.name,b.name) != 0 ) return strcmp(a.name,b.name) < 0;
	else return a.id < b.id;
}
bool cmp3(record a, record b)
{
	if( a.grade != b.grade ) return a.grade < b.grade;
	else return a.id < b.id;
}

int main()
{
	int n,c;
	scanf("%d %d", &n, &c);
	for( int i=0; i<n; i++){
		scanf("%d %s %d", &stu[i].id, stu[i].name, &stu[i].grade);
	}
	if( c==1 ) sort( stu,stu+n,cmp1 );
	if( c==2 ) sort( stu,stu+n,cmp2 );
	if( c==3 ) sort( stu,stu+n,cmp3 ); 
	for( int i=0; i<n; i++){
		printf("%06d %s %d\n",stu[i].id,stu[i].name,stu[i].grade);
	}	
	
	return 0;
}