A few years ago I solved 200 LeetCode problems and still froze on Mediums I hadn't seen. The breakthrough wasn't another hundred problems. It was a different loop. A problem asks for the longest substring with at most K distinct characters. You've solved sliding window before. Maximum sum subarray of size K, done. Longest substring without repeating characters, done. This third one stalls you. Twe
Opinion: We Ditched All Third-Party Mobile SDKs – Cut App Startup Time by 30% for iOS 18 When iOS 18 launched, our team braced for the usual post-release performance tweaks. Instead, we hit a wall: our flagship app’s cold startup time had crept up to 2.8 seconds, well above Apple’s recommended 1.5-second threshold for optimal user retention. After months of debugging, we made a radical call: rem