Problem Solving Training Problem Solving Training for computer science students. Are you looking for a 6-week individual mentorship program? fill an application Level 1: Programming Languages (6 online judges) HackerRank LeetCode AtCoder Codeforces HackerEarth UVA Level 2: Data Structures and Algorithms (6 online judges) HackerRank LeetCode AtCoder Codeforces HackerEarth UVA Level 3: Data Structures and Algorithms (6 online judges) HackerRank LeetCode Google Competitions Codeforces HackerEarth UVA Level 4: Advanced Data Structures and Algorithms (6 online judges) HackerRank LeetCode Google Competitions AtCoder Codeforces HackerEarth Level 5: Advanced Data Structures and Algorithms