Created
February 5, 2020 08:45
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// https://leetcode.com/problems/unique-binary-search-trees-ii/ | |
/** | |
* Definition for a binary tree node. | |
* type TreeNode struct { | |
* Val int | |
* Left *TreeNode | |
* Right *TreeNode | |
* } | |
*/ | |
func generateTrees(n int) []*TreeNode { | |
if n == 0 { | |
return []*TreeNode{} | |
} | |
return generateTreesInRange(1, n) | |
} | |
func generateTreesInRange(min, max int) []*TreeNode { | |
var trees []*TreeNode | |
for val := min; val <= max; val++ { | |
leftSubTrees := generateTreesInRange(min, val - 1) | |
rightSubTrees := generateTreesInRange(val + 1, max) | |
for _, left := range leftSubTrees { | |
for _, right := range rightSubTrees { | |
trees = append(trees, &TreeNode{ | |
Val: val, | |
Left: left, | |
Right: right, | |
}) | |
} | |
} | |
} | |
if len(trees) == 0 { | |
trees = append(trees, nil) | |
} | |
return trees | |
} |
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