AlgoExpert First Non-Repeating Character

Author: raul-sauco

README.md

@@ -987,15 +987,18 @@ First column links to the problem in AlgoExpert, second is the problem's difficu
 
 [🔝 Back to Top 🔝](#coding-challenges)
 
-| AlgoExpert Link                           | Difficulty   | Solutions                                        |
-| ----------------------------------------- | ------------ | ------------------------------------------------ |
-| [Generate Document][ae&generate-document] | 🟢 Easy      | [![python](res/py.png)][ae&generate-document#py] |
-| [Insertion Sort][ae&insertion-sort]       | 🟢 Easy      | [![python](res/py.png)][ae&insertion-sort#py]    |
-| [Merge Sort][ae&merge-sort]               | 🟣 Very Hard | [![python](res/py.png)][ae&merge-sort#py]        |
-| [Remove Islands][ae&remove-islands]       | 🟠 Medium    | [![python](res/py.png)][ae&remove-islands#py]    |
+| AlgoExpert Link                                                   | Difficulty   | Solutions                                                    |
+| ----------------------------------------------------------------- | ------------ | ------------------------------------------------------------ |
+| [First Non-Repeating Character][ae&first-non-repeating-character] | 🟢 Easy      | [![python](res/py.png)][ae&first-non-repeating-character#py] |
+| [Generate Document][ae&generate-document]                         | 🟢 Easy      | [![python](res/py.png)][ae&generate-document#py]             |
+| [Insertion Sort][ae&insertion-sort]                               | 🟢 Easy      | [![python](res/py.png)][ae&insertion-sort#py]                |
+| [Merge Sort][ae&merge-sort]                                       | 🟣 Very Hard | [![python](res/py.png)][ae&merge-sort#py]                    |
+| [Remove Islands][ae&remove-islands]                               | 🟠 Medium    | [![python](res/py.png)][ae&remove-islands#py]                |
 
 [🔝 Back to Top 🔝](#coding-challenges)
 
+[ae&first-non-repeating-character]: https://www.algoexpert.io/questions/first-non-repeating-character
+[ae&first-non-repeating-character#py]: algoexpert/first-non-repeating-character.py
 [ae&generate-document]: https://www.algoexpert.io/questions/generate-document
 [ae&generate-document#py]: algoexpert/generate-document.py
 [ae&insertion-sort]: https://www.algoexpert.io/questions/merge-sort

algoexpert/first-non-repeating-character.py

@@ -0,0 +1,47 @@
+# First Non-Repeating Character
+# 🟢 Easy
+#
+# https://www.algoexpert.io/questions/first-non-repeating-character
+#
+# Tags: String - Hash Map
+
+import timeit
+from collections import Counter
+
+
+class Solution:
+    def firstNonRepeatingCharacter(self, string: str) -> int:
+        # Write your code here.
+        freq = Counter(string)
+        for i, c in enumerate(string):
+            if freq[c] == 1:
+                return i
+        # There are not non-repeating characters.
+        return -1
+
+
+def test():
+    executors = [Solution]
+    tests = [
+        ["abcdcaf", 1],
+        ["faadabcbbebdf", 6],
+    ]
+    for executor in executors:
+        start = timeit.default_timer()
+        for _ in range(1):
+            for col, t in enumerate(tests):
+                sol = executor()
+                result = sol.firstNonRepeatingCharacter(t[0])
+                exp = t[1]
+                assert result == exp, (
+                    f"\033[93m» {result} <> {exp}\033[91m for"
+                    + f" test {col} using \033[1m{executor.__name__}"
+                )
+        stop = timeit.default_timer()
+        used = str(round(stop - start, 5))
+        cols = "{0:20}{1:10}{2:10}"
+        res = cols.format(executor.__name__, used, "seconds")
+        print(f"\033[92m» {res}\033[0m")
+
+
+test()