Some Leetcode problems can be solved by backtracking and dfs effectively
Some Leetcode problems can be solved by dfs effectively
Some Leetcode problems can be solved by bfs effectively
Some Leetcode problems can be solved by divide and conquer effectively
Some Leetcode problems can be solved by binary search effectively
Some Leetcode problems can be solved by greedy algorithm effectively
Some Leetcode problems can be solved by HeapSort & Quick Select effectively