Back when I was in high school I learned all leetcode algorithms from doing programming competitions. One of the books I used was: http://acm.cs.buap.mx/downloa

Back when I was in high school I learned all leetcode algorithms from doing programming competitions. One of the books I used was: http://acm.cs.buap.mx/downloads/Programming_Challenges.pdf http://acm.cs.buap.mx/downloads/Programming_Challenges.pdf What really put me to the next level is this amazing free training program which I still recommend anyone who wants to nail the interviews. It teaches each algorithm and data structure and gives you appropriate challenging exercises so you really understand them: https://train.usaco.org/ https://train.usaco.org/