# Concepts

- [Time Complexity(TC)](/interview-prep/concepts/time-complexity-tc.md)
- [Permutation, Combination and Subset](/interview-prep/concepts/permutation-combination-and-subset.md)
- [Subarray, Subsequence and Subset](/interview-prep/concepts/subarray-subsequence-and-subset.md)
- [Floor and Ceiling of number](/interview-prep/concepts/floor-and-ceiling-of-number.md)
- [Modulo Congurence](/interview-prep/concepts/modulo-congurence.md)
- [Arrays and their sorted orders](/interview-prep/concepts/arrays-and-their-sorted-orders.md)