improve -Implemented the first occurrence algorithm with technique.

Author: phoenix-deb

first_occurrence.py

@@ -0,0 +1,10 @@
+def first_occurrence(array: list[int], target: int) -> int:
+    pointer = 0
+
+    while pointer < len(array):
+        if array[pointer] == target:
+           return pointer
+        pointer += 1
+
+    return -1
+