added dominoes problem for strings in python

Python/strDominoes.py

@@ -0,0 +1,57 @@
+class Solution:
+    def pushDominoes(self, string: str) -> str:
+        low, high = 0, len(string) - 1
+        string = list(string)
+
+        if string[low] == ".":
+            for i in range(len(string)):
+                if string[i] == "R": 
+                    low = i
+                    break
+
+                if string[i] == "L":
+                    for j in range(i):
+                        string[j] = "L"
+                    break
+
+        if string[high] == ".":
+            for i in range(len(string)-1,-1,-1):
+                if string[i] == "L": 
+                    high = i
+                    break
+
+                if string[i] == "R":
+                    for j in range(i, len(string)):
+                        string[j] = "R"
+                    break
+
+        i = low
+        for j in range(low+1, high+1):
+            if string[i] == "R" and string[j] == "L":
+                mid = (i+j) //2 
+                temp = j
+                while i != j:
+                    if i >= temp:
+                        i = j
+                        break
+
+                    string[i] = "R"
+                    string[temp] = "L"
+
+                    temp-=1
+                    i+=1
+
+            if string[i] == "R" and string[j] == "R":
+                while i != j:
+                    string[i] = "R"
+                    i+=1
+
+            if string[i] == "L" and string[j] == "L":
+                while i != j:
+                    string[i] = "L"
+                    i+=1
+
+            if string[i] == "L" and string[j] == "R":
+                i = j
+
+        return "".join(string)