刚健朴实的递归,不过要注意递归跳出的条件和递归进入的条件,不然很容易死循环然后爆栈或者越界。
问题链接:https://leetcode-cn.com/problems/maximum-binary-tree/
代码:
public TreeNode constructMaximumBinaryTree(int[] nums) {
return BinaryTree(nums,0,nums.length-1);
}
public TreeNode BinaryTree(int[] nums,int begin,int end) {
int index = searchMax(nums,begin,end);
if(index==-1){
return null;
}
TreeNode t =new TreeNode(nums[index]);
t.left = BinaryTree(nums,begin,index-1);
t.right = BinaryTree(nums,index+1,end);
return t;
}
int searchMax(int[] num,int start,int end){
int MAX=Integer.MIN_VALUE;
int index = -1;
for(int i=start;i<=end;i++){
if(num[i]>MAX){
MAX=num[i];
index = i;
}
}
return index;
}