数字统计问题

1. #include <iostream>
2. #include <string>
3. #include <sstream>
4. #include <cmath>
5. #include <vector>
7. using namespace std;
9. double string_to_num(string str)
10. {
11.     double back;
12.     istringstream instr(str);
13.     instr>>back;
14.     return back;
15. }
17. int main()
18. {
20.     int len;
21.     double mm; 
22.     int countNum[10] = {0};
23.     vector<int> posNum;
24.     string pageNum;
25.     
26.     cin>>pageNum;
28.     double num = string_to_num(pageNum);
30.     len = pageNum.size();
31.     
32.     if( len <= 1 )
33.     {
34.         for(int i = 1; i <= int(num); i++)
35.             countNum[i] += 1;
36.     }
37.     else{
38.         const char* p = pageNum.c_str();
40.                 for(int i = 0; i < len; i++)
41.                 {
42.                         int highPosNum = int( *(p+i) ) - 48;
43.                             
44.                         mm = pow(10.0,len-i-2) * (len-i-1);
46.                         if( mm != 0)
47.                         {
48.                                 for(int j = 0; j < highPosNum; j++)
49.                                 {
50.                                         for(int k = 0; k < 10; k++)
51.                                             countNum[k] += mm;
53.                                         countNum[j] += pow(10.0,len-i-1);
55.                                         
56.                                 }
57.                                 
58.                                 if( !posNum.empty() )
59.                                 {
60.                                     for(int m = 0; m < posNum.size(); m++)
61.                                     {
62.                                         int tt = posNum.at(m);
63.                                         
64.                                         countNum[tt] += ( pow(10.0,len-i-1)*highPosNum );
65.                                     }       
66.                                 }   
68.                                 posNum.push_back(highPosNum);
70.                                 if( i == 0)
71.                                 {
72.                                     for(int j = 0; j < len-1; j++)
73.                                         countNum[0] = countNum[0] - (len-j-1)*pow(10.0,j)*9.0;
75.                                     countNum[0] -= len;
76.                                 }                       
77.                         }
78.                         else{
79.                                 countNum[0] += 1;
80.                                 for(int m = 0; m < posNum.size(); m++)
81.                                 {
82.                                     int tm = posNum.at(m);
83.                                     countNum[tm] += 1;
84.                                 }
85.                                 
86.                                 for(int n = 1; n <= highPosNum; n++)
87.                                 {
88.                                     countNum[n] += 1;
89.                                     for(int mn = 0; mn < posNum.size(); mn++)
90.                                     {
91.                                         int tmn = posNum.at(mn);
92.                                         countNum[tmn] += 1;
93.                                     }
94.                                 }
95.                             }
96.                 }
97.     }
98.     
99.     for(int i = 0; i < 10; i++)
100.         cout<<countNum[i]<<endl;
102.     return 0;
103. }