a1028 list sorting

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

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).

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.

3 1 
000007 James 85 
000010 Amy 90 
000001 Zoe 60 

000001 Zoe 60 
000007 James 85 
000010 Amy 90 

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

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

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

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

#include <bits/stdc++.h>
using namespace std;

struct Student
{
    int id;
    char name[9];
    int score;
} student[100001];

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

bool cmp2(Student s1, Student s2)
{
    int val = strcmp(s1.name, s2.name);
    if (val != 0)
        return val < 0;
    else
        return s1.id < s2.id;
}

bool cmp3(Student s1, Student s2)
{
    if (s1.score != s2.score)
        return s1.score < s2.score;
    else
        return s1.id < s2.id;
}

int main()
{
    int N, C;
    scanf("%d%d", &N, &C);
    for (int i = 0; i < N; i++)
        scanf("%d%s%d", &student[i].id, student[i].name, &student[i].score);

    if (C == 1)
        sort(student, student + N, cmp1);
    else if (C == 2)
        sort(student, student + N, cmp2);
    else
        sort(student, student + N, cmp3);

    for (int i = 0; i < N; i++)
        printf("%06d %s %dn", student[i].id, student[i].name, student[i].score);
    return 0;
}