uva 10706 Number Sequence

Number Sequence
Input: standard input
Output: standard output
Time Limit: 1 second

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…S_k. Each group S_k consists of a sequence of positive integer numbers ranging from 1 to k, written one after another. For example, the first 80digits of the sequence are as follows:

11212312341234512345612345671234567812345678912345678910123456789101112345678910

Input

The first line of the input file contains a single integer t (1 <=t <=25), 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                           Output for Sample Input

2

8

3

2

2

 

题意：给一个有规律的字符串：

11212312341234512345612345671234567812345678912345678910123456789101112345678910

求出第i位上的数是多少

 

#include <stdio.h>#include <string.h>#include <math.h>long long int a[100];int main(){long long int i,j,n,m,s,pre,t,sum;scanf("%lld",&t);while(t--){scanf("%lld",&n);pre=s=m=0;for(i=1;;i++){ j=i; sum=0;while(j!=0){ j=j/10;  sum++;    }m+=sum;s+=m;  if(s>=n)  {      break;         }   pre=s;    }    n=n-pre;for(i=1,s=0;;i++){    j=i;    sum=0;  while(j!=0){ a[sum++]=j%10;  j=j/10; } if(s+sum>=n) { break; }  s=s+sum;        }printf("%lld\n",a[sum-n+s]);    }    return 0;}