CCPC2018-湖南全国邀请赛-重现赛F题sorting

Sorting

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 0    Accepted Submission(s): 0

Problem Description

Bobo has  n tuples  (a1,b1,c1),(a2,b2,c2),…,(an,bn,cn).
He would like to find the lexicographically smallest permutation  p1,p2,…,pn of  1,2,…,n such that for  i∈{2,3,…,n} it holds that

api−1+bpi−1api−1+bpi−1+cpi−1≤api+bpiapi+bpi+cpi.

 

Input

The input consists of several test cases and is terminated by end-of-file.

The first line of each test case contains an integer  n.
The  i-th of the following  n lines contains  3 integers  ai,  bi and  ci.

 

Output

For each test case, print  n integers  p1,p2,…,pn seperated by spaces.
DO NOT print trailing spaces.

## Constraint

*  1≤n≤103
*  1≤ai,bi,ci≤2×109
* The sum of  n does not exceed  104.

 

Sample Input

2 1 1 1 1 1 2 2 1 1 2 1 1 1 3 1 3 1 2 2 1 3 1 1

 

Sample Output

2 1 1 2

1 2 3

题解：相邻两组的a[i-1],b[i-1],c[i-1]和a[i],b[i],c[i]满足上面的公式，如果相等的话就不交换两组的顺序。

代码：一开始我把大于和小于两种情况一起考虑，在排序的时候把相等的交换了位置，然后一直在wa。。。，果然还是太菜了。。

#include 
#include 
#include 
#include 
#include 

using namespace std;

const int MAX=10010;

struct node{
    long double x,y,z;
}a[MAX];
int b[MAX];

int main(){
    int n;
    while(cin >> n){
        for(int i = 1;i<=n;++i){
            cin >> a[i].x >> a[i].y >> a[i].z;
            b[i] = i;
        }
        for(int i = 1;i<=n;++i){
            for(int j = i+1;j<=n;++j){
                if(a[j].z*(a[i].x+a[i].y)>a[i].z*(a[j].x+a[j].y)){
                    swap(b[i],b[j]);
                    swap(a[i],a[j]); 
                }
                else if(a[j].z*(a[i].x+a[i].y)==a[i].z*(a[j].x+a[j].y) && b[i]>b[j]){
                    swap(b[i],b[j]);
                    swap(a[i],a[j]);
                }
        }
    }
        for(int i = 1;i<=n;++i){
            printf(i==1?"%d":" %d",b[i]);
        }
        cout << endl;
    }
    return 0;
}