LintCode 108. 分割回文串 II
给定字符串 s, 需要将它分割成一些子串, 使得每个子串都是回文串.最少需要分割几次?
Code
def minCut(self, s):
# write your code here
if len(s)==0:
return 0
n=len(s)
Judge=[[False for _ in range(n)] for _ in range(n)]
for i in range(0,n,1):
for j in range(i,n,1):
Judge[i][j]=False
for j in range(n):#奇数
i = j
while i >= 0 and j < n and s[i] == s[j]:
Judge[i][j] = True
i -= 1
j += 1
for j in range(1, n): #偶数
i = j - 1
while i >= 0 and j < n and s[i] == s[j]:
Judge[i][j] = True
i -= 1
j += 1
dp=[[0] for _ in range(n+1)]
dp[0]=0
for j in range(1, n+1,1):
dp[j] = float('inf')
for i in range(0,j,1):
if Judge[i][j-1]:#是不是回文字符串
dp[j] = min(dp[j], dp[i] + 1)
return dp[n]-1#要求,最少需要分割几次?
想法
1.dp[i] + 1 为前i个字符可以划分成几个字符串。
2.最后一步就是最后一段