HDU 1597 find the nth digit

find the nth digit

Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%I64d & %I64u

Submit Status Practice HDU 1597

Description

假设： 
S1 = 1 
S2 = 12 
S3 = 123 
S4 = 1234 
......... 
S9 = 123456789 
S10 = 1234567891 
S11 = 12345678912 
............ 
S18 = 123456789123456789 
.................. 
现在我们把所有的串连接起来 
S = 1121231234.......123456789123456789112345678912......... 
那么你能告诉我在S串中的第N个数字是多少吗？ 

 

Input

输入首先是一个数字K，代表有K次询问。 
接下来的K行每行有一个整数N(1 <= N < 2^31)。

 

Output

对于每个N，输出S中第N个对应的数字. 

 

Sample Input

61234510 

 

Sample Output

112124 

一点一点的找   

#include <iostream>#include <algorithm>#include <stdio.h>#include <string.h>using namespace std;int a[46] = {1,1,2,1,2,3,1,2,3,4,1,2,3,4,5,1,2,3,4,5,6,1,2,3,4,5,6,7,1,2,3,4,5,6,7,8,1,2,3,4,5,6,7,8,9};int main(){int k;scanf("%d", &k);while(k--){long long n;scanf("%d", &n);int flag = 0;if(n <= 45)cout << a[n - 1] << endl;else {n = n - 45;for(int i = 1; ; ++i){for(int j = 1; j <= 9; ++j){if(n <= (9 * i) + j){if(n % 9 == 0)cout << "9" << endl;elsecout << n % 9 << endl;flag = 1;break;}else {n -= (9 * i + j);}//cout << "N : " << n << endl;}if(flag == 1)break;}}}return 0;}