C语言//参考思路:把二叉树按照前序遍历把节点值压入栈,根据栈是否单调递增判断void recursion(struct TreeNode* node, int *stack, int *st_i){ if(node == NULL)return; recursion(node->left, stack, st_i); //前序遍历,把节点值压入栈 stack[(*st_i)++] = node->val; recursion(node->right, stack, st_...