You are given an array a with n distinct integers. Construct an array b by permuting a such that for every non-empty subset of indices S = {x1, x2, ..., xk} (1 ≤ xi ≤ n, 0 < k < n) the sums of elements on that positions in a and b are different, i. e.
The first line contains one integer n (1 ≤ n ≤ 22) — the size of the array.
The second line contains n space-separated distinct integers a1, a2, ..., an (0 ≤ ai ≤ 109) — the elements of the array.
If there is no such array b, print -1.
Otherwise in the only line print n space-separated integers b1, b2, ..., bn. Note that b must be a permutation of a.
If there are multiple answers, print any of them.
2
1 2
2 1
4
1000 100 10 1
100 1 1000 10
An array x is a permutation of y, if we can shuffle elements of y such that it will coincide with x.
Note that the empty subset and the subset containing all indices are not counted.
思路:
每次b对应位置的元素是a对应位置刚好比a小一点的那个元素。
AC code
#include<bits/stdc++.h>
using namespace std;
int a[25],b[25],sub[25];
bool cmp(int x,int y)
{
return a[x]<a[y];
}
int main()
{
int n;cin>>n;
for(int i=1;i<=n;i++)
{
scanf("%d",&a[i]);
sub[i]=i;
}
sort(sub+1,sub+n+1,cmp);
for(int i=1;i<n;i++)
b[sub[i+1]]=a[sub[i]];
b[sub[1]]=a[sub[n]];
for(int i=1;i<n;i++)
cout<<b[i]<<" ";
cout<<b[n]<<endl;
return 0;
}