Time Limit: 1000MS Memory Limit: 10000K
Total Submissions: 17288 Accepted: 4563
Description
A single positive integer i is given. Write a program to find the digit located in the position i in the sequence of number groups S1S2...Sk. Each group Sk consists of a sequence of positive integer numbers ranging from 1 to k, written one after another.
For example, the first 80 digits of the sequence are as follows:
11212312341234512345612345671234567812345678912345678910123456789101112345678910
Input
The first line of the input file contains a single integer t (1 ≤ t ≤ 10), the number of test cases, followed by one line for each test case. The line for a test case contains the single integer i (1 ≤ i ≤ 2147483647)
Output
There should be one output line per test case containing the digit located in the position i.
Sample Input
2
8
3
Sample Output
2
2
Source
Tehran 2002, First Iran Nationwide Internet Programming Contest
//
#include < iostream >
#include < sstream >
using namespace std;
inline int getlen( int i)
{
if (i < 10 ) return 1 ;
else if (i < 100 ) return 2 ;
else if (i < 1000 ) return 3 ;
else if (i < 10000 ) return 4 ;
else if (i < 100000 ) return 5 ;
return 0 ;
}
inline char getchar( int num, int p)
{
stringstream ss;
ss << num;
string s;
ss >> s;
return s[p - 1 ];
}
int main( int argc, char * argv[])
{
// init table
const int SIZE = 40000 ;
__int64 sum[SIZE];
sum[ 0 ] = 0 ;
for ( int i = 1 ;i < SIZE; ++ i)
sum[i] = sum[i - 1 ] + getlen(i);
for ( int i = 1 ; i < SIZE; ++ i)
sum[i] += sum[i - 1 ];
int cases;
scanf( " %d " , & cases);
__int64 num;
for ( int c = 0 ; c < cases; ++ c)
{
scanf( " %I64d " , & num);
// Kth group
int k = 1 ;
while (sum[k] < num) ++ k;
// posth character of number i
int pos = num - sum[k - 1 ];
int i = 1 ;
while (pos - getlen(i) > 0 ) pos -= getlen(i), ++ i;
cout << getchar(i,pos) << endl;
}
return 0 ;
}
Reproduced in: https: //www.cnblogs.com/asuran/archive/2009/10/17/1584885.html