HTML Entity Parser — LeetCode 1410 Python Solution

The problem

HTML entity parser is the parser that takes HTML code as input and replace all the entities of the special characters by the characters itself. The special characters and their entities for HTML are: Quotation Mark: the entity is " and symbol character is ".

Example

Input

text = "& is an HTML entity but &ambassador; is not."

Output

"& is an HTML entity but &ambassador; is not."

Explanation

The parser will replace the & entity by &

Python solution

class Solution:
    def entityParser(self, text: str) -> str:
        d = {
            '"': '"',
            ''': "'",
            '&': "&",
            ">": '>',
            "&lt;": '<',
            "&frasl;": '/',
        }
        i, n = 0, len(text)
        ans = []
        while i < n:
            for l in range(1, 8):
                j = i + l
                if text[i:j] in d:
                    ans.append(d[text[i:j]])
                    i = j
                    break
            else:
                ans.append(text[i])
                i += 1
        return ''.join(ans)

Complexity

Pattern: Hash Map

Trade memory for time: remember what you have seen so the second pass never happens. LeetCode 1410. HTML Entity Parser is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Hash Table.

The hash map guide has the Python template for the pattern and the 709 LeetCode problems that use it.

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