UVa 10706 - Number Sequence

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

A single positiveinteger iis given. Write a program to find the digitlocated in the positioniin the sequence of number groups S₁S₂…S_k. Each groupS_k consists of a sequence of positive integer numbers ranging from1to k, written one after another. For example, the first80 digitsof the sequence are as follows:

11212312341234512345612345671234567812345678912345678910123456789101112345678910

Input

The first line ofthe input file contains a single integer t (1 <=t <=25), thenumber of test cases, followed by one line for each test case. The line for atest case contains the single integeri (1 <=i <=2147483647)

 

Output

There should be one output line per test casecontaining the digit located in the positioni.

 

SampleInput                           Outputfor Sample Input

2

8

3

2

2

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Problem source: Iranian Contest

Special Thanks: Shahriar Manzoor, EPS.

  注意序列的变化

#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;}