Missing: Climbing Stairs leetcode no. 70

[SidharthSarangi]

Assign me to this @KhushbooGoel01

Will be working on C++ for this.

[SahuSumanta]

@KhushbooGoel01 Assign this issue to me.

[SahuSumanta]

i am already familiar with this kind of problems in java

[arushi-2298]

plz assign it to me @KhushbooGoel01