Solution.cpp

class Solution {
public:
    int findNthDigit(int n) {
        int k = 1, cnt = 9;
        while (1ll * k * cnt < n) {
            n -= k * cnt;
            ++k;
            cnt *= 10;
        }
        int num = pow(10, k - 1) + (n - 1) / k;
        int idx = (n - 1) % k;
        return to_string(num)[idx] - '0';
    }
};