May 02

Author: siddydutta

2025-05-May-LeetCoding-Challenge/Push Dominoes.py

@@ -0,0 +1,49 @@
+class Solution:
+    def pushDominoes(self, dominoes: str) -> str:
+        n = len(dominoes)
+        forces = [0] * n
+
+        # forward pass
+        force = 0
+        for i in range(n):
+            if dominoes[i] == 'L':
+                force = 0
+            elif dominoes[i] == 'R':
+                force = n
+            else:
+                force = max(0, force - 1)
+            forces[i] += force
+
+        # backward pass
+        force = 0
+        for i in range(n - 1, -1, -1):
+            if dominoes[i] == 'L':
+                force = n
+            elif dominoes[i] == 'R':
+                force = 0
+            else:
+                force = max(0, force - 1)
+            forces[i] -= force
+
+        # final state
+        result = ''
+        for force in forces:
+            if force > 0:
+                result += 'R'
+            elif force < 0:
+                result += 'L'
+            else:
+                result += '.'
+        return result
+
+
+def main():
+    dominoes = 'RR.L'
+    assert Solution().pushDominoes(dominoes) == 'RR.L'
+
+    dominoes = '.L.R...LR..L..'
+    assert Solution().pushDominoes(dominoes) == 'LL.RR.LLRRLL..'
+
+
+if __name__ == '__main__':
+    main()

2025-05-May-LeetCoding-Challenge/README.md

@@ -5,7 +5,7 @@
 | Day | Problem | Level | Status |
 | --- | --- | --- | --- |
 | May 01 | [2071. Maximum Number of Tasks You Can Assign](https://leetcode.com/problems/maximum-number-of-tasks-you-can-assign/) | Hard | Solved |
-| May 02 | []() |  |  |
+| May 02 | [838. Push Dominoes](https://leetcode.com/problems/push-dominoes/) | Medium | Solved |
 | May 03 | []() |  |  |
 | May 04 | []() |  |  |
 | May 05 | []() |  |  |
@@ -41,5 +41,5 @@
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
 | Easy   | 0 | 0 | 0 |
-| Medium | 0 | 0 | 0 |
+| Medium | 1 | 1 | 0 |
 | Hard   | 1 | 1 | 0 |