PAT甲级——A1028 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 (≤) 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

#include <iostream>
#include<string>
#include <vector>
#include<map>
#include <algorithm>
using namespace std;
struct Node
{
    int ID, grade;
    string name;
};
typedef bool(*funptr)(Node a, Node b);
bool cmp1(Node a, Node b)
{
    return a.ID < b.ID;
}
bool cmp2(Node a, Node b)
{
    return (a.name == b.name) ? a.ID < b.ID : a.name < b.name;
}
bool cmp3(Node a, Node b)
{
    return (a.grade == b.grade) ? a.ID < b.ID : a.grade < b.grade;
}

int main()
{
    int N, C;
    cin >> N >> C;
    vector<Node>v;
    funptr ptr[3] = { &cmp1,&cmp2,&cmp3 };
    for (int i = 0; i < N; ++i)
    {
        Node node;
        cin >> node.ID >> node.name >> node.grade;
        v.push_back(node);
    }
    //使用函数指针
    //sort(v.begin(), v.end(), *(ptr[C - 1]));

    //使用普通方法
    if (C == 1)
        sort(v.begin(), v.end(), [](Node a, Node b) {return a.ID < b.ID; });
    else if (C == 2)
        sort(v.begin(), v.end(), [](Node a, Node b) {return (a.name == b.name) ? a.ID < b.ID : a.name < b.name; });
    else
        sort(v.begin(), v.end(), [](Node a, Node b) {return (a.grade == b.grade) ? a.ID < b.ID : a.grade < b.grade; });
    for (auto a : v)
        cout << a.ID << " " << a.name << " " << a.grade << endl;
    return 0;
}