Create minimum-cost-for-tickets.py

Author: kamyu104

Python/minimum-cost-for-tickets.py

@@ -0,0 +1,21 @@
+# Time:  O(n)
+# space: O(n)
+
+class Solution(object):
+    def mincostTickets(self, days, costs):
+        """
+        :type days: List[int]
+        :type costs: List[int]
+        :rtype: int
+        """
+        dp = [float('inf') for i in xrange(len(days)+1)]
+        dp[0] = 0
+        last_buy_days = [0, 0, 0]
+        durations = [1, 7, 30]
+        for i in xrange(1,len(days)+1):
+            for j in xrange(len(durations)):
+                while i-1 < len(days) and \
+                      days[i-1] > days[last_buy_days[j]]+durations[j]-1:
+                    last_buy_days[j] += 1
+                dp[i] = min(dp[i], dp[last_buy_days[j]]+costs[j])
+        return dp[-1]