Added 70. Climbing Stairs Java

[PranayChauhan2516]

Pull Request Template

Description

Summary:
You are climbing a stair case. It takes n steps to reach to the top.

Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?

Put check marks:

Have you made changes in README file ?

• Added problem & solution under correct topic.
• Specified Space & Time complexity.
• Specified difficulty level, tag & Note(if any).

Make sure all below guidelines are followed else PR will get Reject:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code so that it is easy to understand
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[GouravRusiya30]

@PranayChauhan2516 This is not the efficient code. Please try to do it in O(1) space.

[PranayChauhan2516]

Done!

[PranayChauhan2516]

@GouravRusiya30 It is now correct!

[GouravRusiya30]

Update Readme for space complexity

[PranayChauhan2516]

@GouravRusiya30 Done sir!

[GouravRusiya30]

Thanks for contributing @PranayChauhan2516

[GouravRusiya30]

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