1147：段式回文（1912 分）

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def zfunc(s):
	n = len(s)
	z, l, r = [0]*n, 0, 0
	for i in range(1,n):
		z[i] = max(min(z[i-l],r-i+1), 0)
		while i+z[i]<n and s[z[i]]==s[i+z[i]]:
			l, r = i, i+z[i]
			z[i] += 1
	return z      # z[i]:lcp(后缀i,后缀0) 

class Solution:
    def longestDecomposition(self, text: str) -> int:
        n = len(text)
        m = n//2
        f = [1]*m+[n%2]
        for i in range(m-1,-1,-1):
            s = text[i:n-i]
            z = zfunc(s)
            for j in range(i,m):
                if z[i-j-1]>=j-i+1:
                    f[i] = max(f[i],2+f[j+1])
        return f[0]

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class Solution:
    def longestDecomposition(self, text: str) -> int:
        n = len(text)
        res,i = 0,0
        for j in range(n//2):
            if text[i:j+1]==text[n-j-1:n-i]:
                res += 2
                i = j+1
        return res+(i<=n-1-i)

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def SA(A):
    def SA_IS(A):
        def equal(p1,p2):
            e1,e2 = LMS.find('*',p1+1),LMS.find('*',p2+1)
            return A[p1:e1+1]==A[p2:e2+1]

        def IS(stars):
            sa = [n]+[-1]*n
            tails = list(accumulate(bucket))
            for i in stars[::-1]:
                sa[tails[A[i]]] = i
                tails[A[i]] -= 1
            heads = list(accumulate([1]+bucket[:-1]))
            for i in range(n+1):
                j = sa[i]-1
                if j>=0 and types[j]=='L':
                    sa[heads[A[j]]] = j
                    heads[A[j]] += 1
            tails = list(accumulate(bucket))
            for i in range(n,-1,-1):
                j = sa[i]-1
                if j >= 0 and types[j] == 'S':
                    sa[tails[A[j]]] = j
                    tails[A[j]] -= 1
            return sa[1:]

        n = len(A)
        types = list('0'*(n-1)+'LS')
        for i in range(n-2,-1,-1):
            types[i] = 'S' if A[i]<A[i+1] else 'L' if A[i]>A[i+1] else types[i+1]
        LMS = ''.join('*' if types[i-1:i+1]==['L','S'] else ' ' for i in range(n+1))
        ct = Counter(A)
        bucket = [ct[x] for x in range(max(ct)+1)]
        stars = [i for i in range(n) if LMS[i]=='*']
        sa = IS(stars)
        d, cnt, prev = {}, 0, -1
        for pos in sa:
            if LMS[pos]=='*':
                cnt += prev<0 or not equal(prev,pos)
                d[pos] = cnt
                prev = pos
        B = [d[pos] for pos in stars]
        d1 = {x-1:i for i,x in enumerate(B)}
        sa1 = [d1[x] for x in range(cnt)] if cnt==len(B) else SA_IS(B)
        return IS([stars[pos] for pos in sa1])
	
    def SA_h(A,sa):
        n = len(A)
        rk, height, h = [0]*n,[0]*n,0
        for i in range(n):
            rk[sa[i]] = i
        for i in range(n):
            h = max(0, h-1)
            j = sa[rk[i]-1] if rk[i] else n
            while max(i,j)+h<n and A[i+h]==A[j+h]:
                h += 1
            height[rk[i]] = h
        return rk, height
    sa = SA_IS(A)           # sa[i]:第i小的后缀编号
    rk, height = SA_h(A,sa) # rk[i]:后缀i的排名
    return sa,rk,height     # height[i]:lcp(sa[i],sa[i-1])

class ST:
    def __init__(self,A):
        f = A[:]
        self.st = st = [f]
        j, N = 1, len(f)
        while 2*j<=N:
            f = [min(f[i],f[i+j]) for i in range(N-2*j+1)]
            st.append(f)
            j <<= 1
            
    def query(self,l,r):
        j = (r-l+1).bit_length()-1
        return min(self.st[j][l],self.st[j][r-(1<<j)+1])

class Solution:
    def longestDecomposition(self, text: str) -> int:
        A = [ord(c)-ord('a') for c in text]
        sa,rk,height = SA(A)
        st = ST(height)
        n = len(A)
        res,i = 0,0
        for j in range(n//2):
            l,r = sorted([rk[i],rk[n-j-1]])
            if st.query(l+1,r)>=j-i+1:
                res += 2
                i = j+1
        return res+(i<=n-1-i)