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 (≤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 90

Sample Output 3:

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

开始觉得本题25分太仁慈了，简直不要太简单。写完后发现超时。。。原来本题要用纯c代码写，否则最后一个数据太多cout,cin输入输出时间太长。

(纯c意味着不仅不能用cin/cout而且不能用string)纯c的函数还不是很熟悉.

要用char二维数组，纯c数组比较大小

strcmp(str1,str2) 字典序 str1<str2:-1 str1==str2:0 str1>str2:1 理解成str1-str2就行了

不能str1-str2 str1>str2 数组名是地址，比较的内存地址编号的大小，没有任何实际意义

#include<bits/stdc++.h>
using namespace std;
struct student{
	char info[4][10];//只是比大小 都设置成string没事 
}stu[100010]; 
int N,C;
bool compare(student a,student b){
	if(strcmp(a.info[C],b.info[C])!=0) return strcmp(a.info[C],b.info[C])<0;//s1<s2:-1  s1==s2:0  s1>s2:1
	return strcmp(a.info[1],b.info[1])<0;
}
int main(){
	//freopen("in.txt","r",stdin);
	cin>>N>>C;
	for(int i=0;i<N;i++){
		for(int j=1;j<=3;j++) scanf("%s",stu[i].info[j]); 
	}
	sort(stu,stu+N,compare);
	for(int i=0;i<N;i++){
		printf("%s %s %s\n",stu[i].info[1],stu[i].info[2],stu[i].info[3]);
	}
	return 0;
}

来源：CSDN

作者：树叶子_

链接：https://blog.csdn.net/hza419763578/article/details/100046349

标签

james