Print array in zigzag order
C/zigzagarray.c

clockwise inward spiral array Print
CPP/clockwiseiterator.cpp

combination of characters
CPP/char_combination.cpp

Reverse stack.
CPP/reverse_stack.cpp

Given an array such that every number differ from its adjacent number by at max 1. Find a number in this array efficiently.
CPP/find_no_in_array.cpp