optimizing

Time limit2sMemory limit1024 MB

Summary

Given n below 2^63, return the digit at index n (0-indexed) of the string formed by concatenating g(0), g(1), g(2), ... where g(k) is the sum of cubes below k.

Level: Medium6 of 10
Topics: Math, Binary search, Implementation
Solved: No attempts yet

Statement

Write a function optimizing.

The input parameter is an int object n satisfying $0\le$ n $<2^{63}$ . The return value is the int object $f(n)$ , where $f$ is the following Python function:

def f(n):
    assert type(n)==int and n>=0
    g=lambda n:sum([x**3 for x in range(n)])
    x=""
    k=0
    while n>=len(x):
        x+=str(g(k))
        k+=1
    return int(x[n])

Examples1

Example 1
Input
```
1
```
Expected output
```
0
```