LeetCode has a great collection of problems that you can practice with and test your solution in the browser (https://oj.leetcode.com/ https://oj.leetcode.com/

LeetCode has a great collection of problems that you can practice with and test your solution in the browser (https://oj.leetcode.com/ https://oj.leetcode.com/). The discussion sections were helpful as well. GeeksforGeeks also has a collection of problems and analyses (http://geeksforgeeks.org/fundamentals-of-algorithms/ http://geeksforgeeks.org/fundamentals-of-algorithms/). So after refreshing yourself on the fundamentals, practice, practice, practice. Hope this helps!