• Time Complexity revisited
• STL

Adhoc ideas:

• Rectangle Geometry and range intersection and union
• Simulation Problems
• Treating permutations as graphs/cycles
• Coordinate Compression
• Recursion and how to think about it

Treating Candidate Problems:

https://codeforces.com/contest/1621/problem/C

Problems:

Vectors

https://codeforces.com/gym/401192/problem/A

Sets

https://codeforces.com/problemset/problem/44/A https://codeforces.com/problemset/problem/780/Ahttps://leetcode.com/problems/first-unique-character-in-a-string/

https://codeforces.com/contest/1714/problem/B

Maps

https://codeforces.com/problemset/problem/44/A https://codeforces.com/problemset/problem/780/A https://leetcode.com/problems/first-unique-character-in-a-string/

Stack