Leetcode 132. Palindrome Partitioning II

求次数的问题一般用DP

 class Solution(object):
     def minCut(self, s):
         """
         :type s: str
         :rtype: int
         """
         n = len(s)
         maxInt = 2147483647
         cuts = [maxInt for x in range(n)]
         p = self.palinTable(s)
         for i in range(n):
             temp = maxInt
             if p[0][i] == True:
                 cuts[i] = 0
             else:
                 for j in range(i):
                     if p[j+1][i] and temp > cuts[j] + 1:
                         temp = cuts[j] + 1
                 cuts[i] = temp
         return cuts[-1]

     def palinTable(self, s):
         n = len(s)

         p = [[False for x in range(n)] for y in range(n)]

         for i in range(n):
             p[i][i] = True

         for i in range(n-1):
             if s[i] == s[i+1]:
                 p[i][i+1] = True

         for curLen in range(3,n+1):
             for i in range(n-curLen+1):
                 j = i + curLen-1
                 if s[i] == s[j] and p[i+1][j-1]:
                     p[i][j] = True

         return p