toj_2903.cpp

Tianjin University Online Judge 的80多道题目 .

/*2903.   Number Sequence Time Limit: 1.0 Seconds   Memory Limit: 65536K
Total Runs: 66   Accepted Runs: 29


This is simple a number sequence problem. In this problem a positive integer n will repeated n times. And number will start with 1 and continue to infinite.

For example: if n is 11 then 11 will repeated 11 times.(11 11 11 11 11 11 11 11 11 11 11).

In this problem you are expected to write a program that take a positive number p and display the digit of position p.

   p| 1   2   3   4   5  6   7   8   9   10   11   12   13   14   15   16   17   18   19   20    21
d(p)| 1   2   2   3   3  3   4   4   4   4     5    5    5    5    5    6    6    6    6    6     6     7

Input:

The input may contain multiple test cases. Each test case occupies a separate line and contains an integer n (1 ≤ n ≤ 199000000 ). The input terminates by end of file marker.

Output:

For each test case in the input output the digit of n position on a separate line.

Sample Input:

1
11
14
19
21
22
46
47
48
49

Sample Output:

1
5
5
6
6
7
1
0
1
0


Problem Setter: MD. SHAKIL AHMED.(CUET AGRODUT)


Source: New Year Challenge Contest*/
#include<cstdio>
#include<cmath>
#define MIN 1e-10
int main()
{
  int p , dp;
  double dpPre;
  while ( scanf( "%d" , &p ) != EOF )
    {
      dpPre = ( -1 + sqrt( 1 + 8 * p ) ) / 2;
      dp = static_cast< int >( dpPre );
      printf( "%lf %d\n" , dpPre , dp );
      if ( fabs( dpPre - dp ) > 1e-10 )
	dp++;
      printf( "%d\n" , dp );
    }
  return 0;
}