结构体~！！！

PM2.5

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 317    Accepted Submission(s): 191

Problem Description

Nowadays we use content of PM2.5 to discribe the quality of air. The lower content of PM2.5 one city have, the better quality of air it have. So we sort the cities according to the content of PM2.5 in asending order.

Sometimes one city’s rank may raise, however the content of PM2.5 of this city may raise too. It means that the quality of this city is not promoted. So this way of sort is not rational. In order to make it reasonable, we come up with a new way to sort the cityes. We order this cities through the diffrence between twice measurement of content of PM2.5 (first measurement – second measurement) in descending order, if there are ties, order them by the second measurement in asending order , if also tie, order them according to the input order.

 

Input

Multi test cases (about 100), every case contains an integer n which represents there are n cities to be sorted in the first line.
Cities are numbered through 0 to n−1.
In the next n lines each line contains two integers which represent the first and second measurement of content of PM2.5
The ith line describes the information of city i−1
Please process to the end of file.

[Technical Specification]
all integers are in the range [1,100]

 

Output

For each case, output the cities’ id in one line according to their order.

 

Sample Input

2
100 1
1 2
3
100 50
3 4
1 2

 

Sample Output

0 1
0 2 1
题记：题目的意思为：给一组数据城市排序，打印出其编号；首先根据两次雾霾含量差值进行排序，若差值相同则根据第二次测量的
数据，谁比较小，就靠前。本题目只能用结构体解答：下面附上代码解析
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
struct pp
{
    int er,cha,id;
}b[110];//结构体的申明
int cmp(const pp &a,const pp &b)
{
    if(a.cha==b.cha)
    {
    if(a.er==b.er)
    return a.id<b.id;
    return a.er<b.er;
    }

    return a.cha<b.cha;
}//判定cmp算法应当注意所有情况的考虑
int main()
{
    int i,j,k,first,se,n;
    while(scanf("%d",&n)!=EOF)
    {
        for(i=0;i<n;i++)
        {
            scanf("%d%d",&first,&se);
            b[i].er=se;b[i].cha=se-first;b[i].id=i;
        }
        sort(b,b+n,cmp);//调用sort算法
        printf("%d",b[0].id);
        for(i=1;i<n;i++)
        printf(" %d",b[i].id);//打印
        printf("\n");
    }
    return 0;

}