Create car-fleet-ii.py

Author: kamyu104

Python/car-fleet-ii.py

@@ -0,0 +1,20 @@
+# Time:  O(n)
+# Space: O(n)
+
+class Solution(object):
+    def getCollisionTimes(self, cars):
+        """
+        :type cars: List[List[int]]
+        :rtype: List[float]
+        """
+        stk = []
+        result = [-1.0]*len(cars)
+        for i in reversed(xrange(len(cars))):
+            p, s = cars[i]
+            while stk and (cars[stk[-1]][1] >= s or 
+                           0 < result[stk[-1]] <= float(cars[stk[-1]][0]-p)/(s-cars[stk[-1]][1])):
+                stk.pop()
+            if stk:
+                result[i] = float(cars[stk[-1]][0]-p)/(s-cars[stk[-1]][1])
+            stk.append(i)
+        return result