Sengoku still remembers the mysterious "colourful meteoroids" she discovered with Lala-chan when they were little. In particular, one of the nights impressed her deeply, giving her the illusion that all her fancies would be realized.
On that night, Sengoku constructed a permutation p1, p2, ..., pn of integers from 1 to n inclusive, with each integer representing a colour, wishing for the colours to see in the coming meteor outburst. Two incredible outbursts then arrived, each with n meteorids, colours of which being integer sequences a1, a2, ..., an and b1, b2, ..., bn respectively. Meteoroids' colours were also between 1 and ninclusive, and the two sequences were not identical, that is, at least one i (1 ≤ i ≤ n) exists, such that ai ≠ bi holds.
Well, she almost had it all — each of the sequences a and b matched exactly n - 1 elements in Sengoku's permutation. In other words, there is exactly one i (1 ≤ i ≤ n) such that ai ≠ pi, and exactly one j (1 ≤ j ≤ n) such that bj ≠ pj.
For now, Sengoku is able to recover the actual colour sequences a and b through astronomical records, but her wishes have been long forgotten. You are to reconstruct any possible permutation Sengoku could have had on that night.
The first line of input contains a positive integer n (2 ≤ n ≤ 1 000) — the length of Sengoku's permutation, being the length of both meteor outbursts at the same time.
The second line contains n space-separated integers a1, a2, ..., an (1 ≤ ai ≤ n) — the sequence of colours in the first meteor outburst.
The third line contains n space-separated integers b1, b2, ..., bn (1 ≤ bi ≤ n) — the sequence of colours in the second meteor outburst. At least one i (1 ≤ i ≤ n) exists, such that ai ≠ bi holds.
Output n space-separated integers p1, p2, ..., pn, denoting a possible permutation Sengoku could have had. If there are more than one possible answer, output any one of them.
Input guarantees that such permutation exists.
5 1 2 3 4 3 1 2 5 4 5
1 2 5 4 3
5 4 4 2 3 1 5 4 5 3 1
5 4 2 3 1
4 1 1 3 4 1 4 3 4
1 2 3 4
In the first sample, both 1, 2, 5, 4, 3 and 1, 2, 3, 4, 5 are acceptable outputs.
In the second sample, 5, 4, 2, 3, 1 is the only permutation to satisfy the constraints.
贪心~
因为一定有答案,所以只有两个位置不同和一个位置不同两种情况。
分类讨论:当有一个位置不同时,我们记录出现过那些数,剩下的一个填入这个位置中。
当有两个位置不同是,我们记录剩下的两个空位,判断取a或b在该位的数是否会导致重复。
#include<cstdio>
#include<iostream>
using namespace std;
int n,a[1001],b[1001],c[1001],tot,now,d[1001],x[1001];
bool k[1001];
int main()
{
scanf("%d",&n);
for(int i=1;i<=n;i++) scanf("%d",&a[i]);
for(int i=1;i<=n;i++) scanf("%d",&b[i]);
for(int i=1;i<=n;i++) if(b[i]!=a[i]) tot++;
if(tot==1)
{
for(int i=1;i<=n;i++) if(a[i]==b[i]) c[i]=a[i],k[c[i]]=1;
else now=i;
for(int i=1;i<=n;i++) if(!k[i])
{
c[now]=i;break;
}
}
else
{
for(int i=1;i<=n;i++)
if(a[i]==b[i]) c[i]=a[i],k[c[i]]=1;
else d[tot--]=i;
if(a[d[1]]==b[d[2]] || k[a[d[1]]] || k[b[d[2]]]) c[d[1]]=b[d[1]],c[d[2]]=a[d[2]];
else c[d[1]]=a[d[1]],c[d[2]]=b[d[2]];
}
for(int i=1;i<=n;i++) printf("%d ",c[i]);
return 0;
}