Commit 0e5bfda

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improved code of palindrome-partitioning

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+15

-18

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+15

-18

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Lines changed: 15 additions & 18 deletions

Original file line number	Diff line number	Diff line change
`@@ -259,33 +259,30 @@ class Solution:`
`259`	`259`	`class Solution:`
`260`	`260`	`def partition(self, s: str) -> List[List[str]]:`
`261`	`261`
`262`		`- n = len(s)`
`263`		`- is_Pal = {}`
	`262`	`+ N = len(s)`
	`263`	`+ Pal = collections.defaultdict(set)`
`264`	`264`
`265`	`265`	`def isPal(i, j):`
`266`	`266`	`if i < j:`
`267`		`- return is_Pal[i, j]`
	`267`	`+ return j in Pal[i]`
`268`	`268`	`return True`
`269`	`269`
`270`		`- for i in range(n - 2, -1, -1):`
`271`		`- for j in range(i + 1, n):`
`272`		`- is_Pal[i, j] = s[i] == s[j] and isPal(i + 1, j - 1)`
	`270`	`+ for j in range(N):`
	`271`	`+ for i in range(j + 1):`
	`272`	`+ if s[i] == s[j] and isPal(i + 1, j - 1):`
	`273`	`+ Pal[i].add(j)`
`273`	`274`
`274`	`275`	`result = []`
`275`	`276`
`276`		`- def backtrack(left=-1, right=-1, route=[]):`
`277`		`-`
`278`		`- if not isPal(left, right):`
`279`		`- return`
`280`		`-`
`281`		`- if right == n - 1:`
`282`		`- result.append(route.copy())`
	`277`	`+ def backtrack(first=0, route=[]):`
	`278`	`+`
	`279`	`+ if first == N:`
	`280`	`+ result.append(route[:])`
`283`	`281`	`return`
`284`		`-`
`285`		`- left = right + 1`
`286`		`- for i in range(left, n):`
`287`		`- route.append(s[left:i + 1])`
`288`		`- backtrack(left, i, route)`
	`282`	`+`
	`283`	`+ for i in Pal[first]:`
	`284`	`+ route.append(s[first:i+1])`
	`285`	`+ backtrack(i + 1)`
`289`	`286`	`route.pop()`
`290`	`287`
`291`	`288`	`return`

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