文章作者：Tyan
博客：noahsnail.com | CSDN | 简书
1. Description
Nth Digit
2. Solution
- Version 1
class Solution {
public:
int findNthDigit(int n) {
int digits = 1;
long base = 9;
while(n > digits * base) {
n -= digits * base;
digits++;
base *= 10;
}
int residual = n % digits;
int quotient = n / digits;
int target = base / 9 + quotient + (residual?1:0) - 1;
if(residual == 0) {
return target % 10;
}
char s = to_string(target)[residual - 1];
return s - '0';
}
};
- Version 2
class Solution {
public:
int findNthDigit(int n) {
int digits = 1;
long base = 9;
while(n > digits * base) {
n -= digits * base;
digits++;
base *= 10;
}
int residual = n % digits;
int quotient = n / digits;
int target = base / 9 + quotient + (residual?1:0) - 1;
int count = digits - residual + 1;
if(residual == 0) {
return target % 10;
}
int result = 0;
while(count) {
result = target % 10;
target /= 10;
count--;
}
return result;
}
};
