I've solved a lot of problems on codeforces, codechef and atcoder. Sorry, not solved, wasted a lot of time. I tried a lot to think logic on problem B of todays contest, but still didn't come up with the solution. I don't know, whether it's a good decision or not, but I'm giving up. Honestly, need some strong intuition to carry one. Please if you have, suggest me.

Why am I not able to solve problems rated more than or equal to 1500? Even, I know every concept which requires for solving that much rated problems? I need some guidance. I feel giving up sometimes, so I need some help who has been gone through this phase.