Simple Python solution_O(n)
Goal: We need to check if all the letters from a-z have occured atleast once or not in a given sentence\n\n### Approach:\n\n- We don\'t care if any letter betwe
__Goal__: We need to check if all the letters from a-z have occured atleast once or not in a given sentence\n\n### Approach:\n\n- We don\'t care if any letter between a-z occurs more than once.\n- So we get only the single occurances of each character in the string by converting it into a set which is an ordered sequence of unique elements.\n- Now, we need to check if all the elements between a-z are there. In other words, if our resulting set has all  the 26 letters of English alphabet\n- So we just check if it\'s length is 26.\n\n```python\nclass Solution:\n    def checkIfPangram(self, sentence: str) -> bool:\n\n        return len(set(sentence)) == 26\n```\n\n__TIME COMPLEXITY__: O(n)\n\n- set(str) would be O(k) where k is the length of the string k . [Reference](https://stackoverflow.com/questions/34642155/what-is-time-complexity-of-a-list-to-set-conversion/34642209)\n- len() has O(1) in python. [Reference](https://stackoverflow.com/questions/1115313/cost-of-len-function)\n\n_NOTE_: In case you have anything to add or suggest any corrections, please do so in the comments. I am open to feedback!
['String', 'Python', 'Python3']