add 0402-remove-k-digits.py

Author: Dhyan-P-Shetty

Diff for: python/0402-remove-k-digits.py

@@ -0,0 +1,13 @@
+class Solution:
+    def removeKdigits(self, num: str, k: int) -> str:
+        stack = []
+        for i in num:
+            while stack and stack[-1] > i and k > 0:
+                k -= 1
+                stack.pop()
+            if stack or i is not "0":
+                stack.append(i)
+        if k:
+            stack = stack[:-k]
+        return ''.join(stack) or '0'
+