A. Beautiful Year
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

It seems like the year of 2013 came only yesterday. Do you know a curious fact? The year of 2013 is the first year after the old 1987 with only distinct digits.

Now you are suggested to solve the following problem: given a year number, find the minimum year number which is strictly larger than the given one and has only distinct digits.

Input

The single line contains integer y (1000 ≤ y ≤ 9000) — the year number.

Output

Print a single integer — the minimum year number that is strictly larger than y and all it's digits are distinct. It is guaranteed that the answer exists.

Examples
input 
1987
output 
2013
input 
2013
output 
2014

【题意】：给你一个数。求大于该数且每个位数不相同。四位数。
【分析】：逆向思维，类似回文串，双重循环，一个指针遍历，另一个指针紧跟其后。两两一相等就return false了。
【代码】：
#include<cstdio>
#include<iostream>
#include<queue>
#include<algorithm>
using namespace std;
bool check(int n)
{
    int i=0,a[4],j;
    while(n)
    {
        a[i++]=n%10;
        n/=10;
    }

    for(int i=0;i<4;i++)
    {
        for(int j=i+1;j<4;j++)
        {
            if(a[i]==a[j])
                return false;
        }
    }
    return true;
}
int main()
{
    int n;
    while(cin>>n)
    {
        for(int i=n+1; ;i++)
        {
            if(check(i))
            {
                cout<<i<<endl;
                break;
            }
        }
    }
    return 0;
}
类似回文串的判断