Create palindrome-partitioning-iv.py

Author: kamyu104

Python/palindrome-partitioning-iv.py

@@ -0,0 +1,52 @@
+# Time:  O(n)
+# Space: O(n)
+
+class Solution(object):
+    def checkPartitioning(self, s):
+        """
+        :type s: str
+        :rtype: bool
+        """
+        def modified_manacher(s):
+            s = '^#' + '#'.join(s) + '#$'
+            P = [0]*len(s)
+            dp1 = [False]*len(s)  # dp1[i]: s[:i] is a palindromic string
+            dp2 = [False]*len(s)  # dp2[i]: s[:i+1] is composed of 2 palindromic strings
+            C, R = 0, 0
+            for i in xrange(1, len(s)-1):
+                i_mirror = 2*C-i
+                if R > i:
+                    P[i] = min(R-i, P[i_mirror])
+                while s[i+1+P[i]] == s[i-1-P[i]]:
+                    if dp1[i-1-P[i]]:
+                        dp2[i+1+P[i]] = True
+                    P[i] += 1
+                if i+1+P[i] == len(s)-1 and dp2[i-1-P[i]]:
+                    return True
+                if i-1-P[i] == 0:
+                    dp1[i+1+P[i]] = True
+                if i+P[i] > R:
+                    C, R = i, i+P[i]
+            return False
+
+        return modified_manacher(s)
+
+
+# Time:  O(n^2)
+# Space: O(n)
+class Solution(object):
+    def checkPartitioning(self, s):
+        """
+        :type s: str
+        :rtype: bool
+        """        
+        dp = [[False]*len(s) for _ in xrange(len(s))]
+        for i in reversed(xrange(len(s))):
+            for j in xrange(i, len(s)):
+                if s[i] == s[j] and (j-i < 2 or dp[i+1][j-1]):
+                    dp[i][j] = True
+        for i in xrange(1, len(s)):
+            for j in xrange(i+1, len(s)):
+                if dp[0][i-1] and dp[i][j-1] and dp[j][-1]:
+                    return True
+        return False