Leetcode Notes:

Summary of question type:

• Two pointer
• Sliding window
• Treenode
• Listnode

Knowledge example:

• python dictionary
• java hashmap

Class:

Java HashMap

Map<Integer, Integer> map = new HashMap<>();
map.put(key, value)     // hash the value to key
map.containsKey(key)    // check if the key is stored in the map
map.get(key)            // get value for a specific key