You count the weeks between today and your on site. Twelve. You pull up a 90 day FAANG prep plan and the structure looks reasonable: easy problems for two weeks, mediums for six, hards for the rest. Six weeks in, you hit binary trees and realise your recursion is shaky. Two weeks later you try a DP problem and can't formulate the recurrence. Suddenly the 12 week plan is a 6 week plan with 6 weeks of rework. Difficulty isn’t the problem. Order is. TL;DR: A 90 day FAANG plan works when topics are ordered by dependency, not by difficulty or popularity. The typical "easy then medium then hard" plan ignores that DP needs recursion, recursion needs the call stack, and the call stack needs array fundamentals. Sequence by what each topic requires , not by how hard it feels. What "wrong order" actually looks like The failure mode in most 90 day plans is the same shape every time. The plan groups topics by surface difficulty: arrays first because they are easy, DP last because it is hard.…