USACO 2.2 Runaround Numbers(乱搞）
效率好低，先DFS预处理所有的数，100万个左右，然后二分找到比n大的，然后枚举判断。
1 /* 2 ID: cuizhe 3 LANG: C++ 4 TASK: runround 5 */ 6 #include <iostream> 7 #include <cstdio> 8 #include <cstring> 9 #include <cstdlib> 10 #include <map> 11 #include <algorithm> 12 #include <ctime> 13 using namespace std; 14 long long p[1000000]; 15 int num,o[11]; 16 void dfs(long long sum) 17 { 18 int i,z; 19 if(sum != 0) 20 p[num++] = sum; 21 z = 0; 22 for(i = 1;i <= 9;i ++) 23 { 24 if(!o[i]) 25 { 26 o[i] = 1; 27 dfs(sum*10+i); 28 o[i] = 0; 29 z = 1; 30 } 31 } 32 if(!z) return ; 33 } 34 int judge(long long n) 35 { 36 int key[13],len,mm[13],ti,i,ll[13]; 37 memset(mm,0,sizeof(mm)); 38 len = 1; 39 while(n) 40 { 41 key[len++] = n%10; 42 n = n/10; 43 } 44 for(i = 1;i <= len-1;i ++) 45 ll[i] = key[len-i]; 46 ti = 1;mm[1] = 1; 47 for(i = 2;i <= len-1;i ++) 48 { 49 ti = (ll[ti]+ti)%(len-1); 50 if(ti == 0) 51 ti = len-1; 52 mm[ti] ++; 53 if(mm[ti] >= 2) 54 return 0; 55 } 56 ti = (ll[ti]+ti)%(len-1); 57 if(ti == 1) 58 return 1; 59 else 60 return 0; 61 } 62 int main() 63 { 64 long long n,str,end,mid; 65 int i; 66 num = 1; 67 freopen("runround.in","r",stdin); 68 freopen("runround.out","w",stdout); 69 dfs(0); 70 sort(p+1,p+num); 71 scanf("%lld",&n); 72 str = 1; 73 end = num-1; 74 while(str < end) 75 { 76 mid = (str+end)/2; 77 if(p[mid] < n) 78 str = mid+1; 79 else 80 end = mid; 81 } 82 if(p[str] == n) 83 str ++; 84 for(i = str;i <= num-1;i ++) 85 { 86 if(judge(p[i])) 87 { 88 printf("%lld\n",p[i]); 89 break; 90 } 91 } 92 return 0; 93 }
