codeforces 224B Undoubtedly Lucky Numbers

题目链接:http://codeforces.com/problemset/problem/244/B

解题思路:DFS 搜索

 1 /**************************************************************************
 2 user_id:                                                    SCNU20102200088
 3 problem_id:                                                 codeforces 244B
 4 problem_name:                                     Undoubtedly Lucky Numbers
 5 **************************************************************************/
 6 
 7 #include <algorithm>
 8 #include <iostream>
 9 #include <iterator>
10 #include <iomanip>
11 #include <sstream>
12 #include <fstream>
13 #include <cstring>
14 #include <cstdlib>
15 #include <climits>
16 #include <bitset>
17 #include <string>
18 #include <vector>
19 #include <cstdio>
20 #include <cctype>
21 #include <ctime>
22 #include <cmath>
23 #include <queue>
24 #include <stack>
25 #include <list>
26 #include <set>
27 #include <map>
28 using namespace std;
29 
30 //线段树
31 #define lson l,m,rt<<1
32 #define rson m+1,r,rt<<1|1
33 
34 //手工扩展栈
35 #pragma comment(linker,"/STACK:102400000,102400000")
36 
37 const double EPS=1e-9;
38 const double PI=acos(-1.0);
39 const double E=2.7182818284590452353602874713526;  //自然对数底数
40 const double R=0.5772156649015328606065120900824;  //欧拉常数:(1+1/2+...+1/n)-ln(n)
41 
42 const int x4[]={-1,0,1,0};
43 const int y4[]={0,1,0,-1};
44 const int x8[]={-1,-1,0,1,1,1,0,-1};
45 const int y8[]={0,1,1,1,0,-1,-1,-1};
46 
47 typedef long long LL;
48 
49 typedef int T;
50 T max(T a,T b){ return a>b? a:b; }
51 T min(T a,T b){ return a<b? a:b; }
52 T gcd(T a,T b){ return b==0? a:gcd(b,a%b); }
53 T lcm(T a,T b){ return a/gcd(a,b)*b; }
54 
55 ///////////////////////////////////////////////////////////////////////////
56 //Add Code:
57 set<LL> s;
58 
59 void DFS(int n,int i,int j,LL res,int cnt){
60     if(res>n || (res==0 && cnt>0)) return ;
61     if(res>0) s.insert(res);
62     DFS(n,i,j,10*res+i,cnt+1);
63     DFS(n,i,j,10*res+j,cnt+1);
64 }
65 ///////////////////////////////////////////////////////////////////////////
66 
67 int main(){
68     std::ios::sync_with_stdio(false);
69     //freopen("in.txt","r",stdin);
70     //freopen("out.txt","w",stdout);
71     ///////////////////////////////////////////////////////////////////////
72     //Add Code:
73     int n,i,j;
74     scanf("%d",&n);
75     for(i=0;i<9;i++){
76         for(j=i+1;j<=9;j++) DFS(n,i,j,0,0);
77     }
78     printf("%d\n",s.size());
79     ///////////////////////////////////////////////////////////////////////
80     return 0;
81 }
82 
83 /**************************************************************************
84 Testcase:
85 Input:
86 10
87 123
88 Output:
89 10
90 113
91 **************************************************************************/

posted on 2013-09-23 21:18  SCNU20102200088  阅读(428)  评论(0编辑  收藏  举报

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