洛谷P1467 循环数 Runaround Numbers

洛谷P1467 循环数 Runaround Numbers

#include <cstdio> 
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <iostream> 
#include <iomanip> 
#include <string> 
#include <algorithm> 
#define LL long long 
#define For(i,j,k) for(int i=j;i<=k;i++) 
#define Dow(i,j,k) for(int i=j;i>=k;i--) 
using namespace std ;  

const int N = 50011 ; 
int n,len ; 
int bit[11],flag[10] ;  

inline int read() 
{
    int x = 0 , f = 1 ; 
    char ch = getchar() ; 
    while(ch<'0'||ch>'9') { if(ch=='-') f = -1 ; ch = getchar(); } 
    while(ch>='0'&&ch<='9') { x = x * 10+ch-48 ; ch = getchar(); } 
    return x * f ; 
}

inline void add() 
{
    bit[0]+=1 ; 
    For(i,0,len-1) 
        if(bit[i]==10) bit[i]=0,bit[i+1]++ ; 
        else return ; 
    if(bit[len]) len++ ; 
}

inline bool check() 
{
    int pos = 0,cnt = 0 ; 
    For(i,0,9) flag[i] = 0 ; 
    For(i,0,len-1) flag[bit[i]]++ ; 
    For(i,1,9) if(flag[i]>1) return 0 ;  
    if(flag[0]) return 0 ; 
    For(i,0,9) flag[i] = 0 ;
    
    For(i,0,(len-1)/2) swap(bit[i],bit[len-1-i]) ; 
    For(i,1,len) {
        (pos+=bit[pos])%=len ; 
        if(!flag[bit[pos]]) cnt++ ; 
        flag[bit[pos]] = 1 ; 
    }
    For(i,0,(len-1)/2) swap(bit[i],bit[len-1-i]) ; 
    if(cnt!=len) return 0 ; 
    if(pos) return 0 ; 
    return 1 ; 
}

inline void write() 
{
    int ans = 0 ; 
    Dow(i,len-1,0)
        (ans*=10)+=bit[i] ; 
    printf("%d
",ans) ; 
    exit(0) ; 
}

int main() 
{
    n = read() ;
    if(n==0) bit[len++]=0 ; 
    while(n) {
        bit[len++]=n%10 ; 
        n/=10 ; 
    }  
    while(1) {
        add() ; 
        if(check()) write() ; 
    }
    return 0 ; 
}