JZ17 树的子结构

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */

func helper( pRoot1 *TreeNode ,  pRoot2 *TreeNode ) bool {
    if pRoot2 == nil {
        return true
    }
    if pRoot1 == nil {
        return false
    }
    if pRoot1.Val != pRoot2.Val {
        return false
    }
    return helper(pRoot1.Left, pRoot2.Left) && helper(pRoot1.Right, pRoot2.Right)
}

func isSubStructure( pRoot1 *TreeNode ,  pRoot2 *TreeNode ) bool {
    // write code here
    if pRoot1 == nil || pRoot2 == nil {
        return false
    }
 
    return helper(pRoot1, pRoot2) || isSubStructure(pRoot1.Left, pRoot2) || isSubStructure(pRoot1.Right, pRoot2)
}