for a big tech job , most of us think we need to be very logical and should spent half of the time on developing our problem solving skills and as a result we register on websites like codeforces,leetcode etc.The problem arises when we start these without any preparation, first we should understand these also take very heavy understanding and not something we can do develop over our free time. we should dedicate some time weekly towards this,practiciing questions . And the most important is this is something that can be only achieved through practice and these are no easy shortcuts for this . Unlike any other skills we should focus practicing new questions to improve our understanding and improve our chance to getting that big dream job.