牛客网：NC98 判断t1树中是否有与t2树完全相同的子树

使用递归，判断每一个是否匹配，匹配返回true，全部都不匹配返回false 

/**
 * @author xienl
 * @description 判断t1树中是否有与t2树完全相同的子树
 * @date 2022/7/1
 */

public class Solution {
    public static void main(String[] args) {
        Solution solution = new Solution();

    }

    public boolean isContains (TreeNode root1, TreeNode root2) {
        // write code here
        if (root1 == null){
            return false;
        }
        return calculation(root1, root2) || isContains(root1.left, root2) || isContains(root1.right, root2);
    }

    private boolean calculation(TreeNode root1, TreeNode root2){
        if (root1 == null && root2 == null){
            return true;
        }
        if (root1 == null || root2 == null || (root1.val != root2.val)){
            return false;
        }
        return calculation(root1.left, root2.left) && calculation(root1.right , root2.right);
    }
}


class TreeNode {
    int val = 0;
    TreeNode left = null;
    TreeNode right = null;
  }