记录下菜鸡写的比较详细的写法
public class JZ4_重建二叉树 { public static TreeNode reConstructBinaryTree(int[] pre, int[] in) { if (pre.length == 0 || in.length == 0) return null; //前序数组的第一个值即接下来的树的头节点 TreeNode root = new TreeNode(pre[0]); //找到前序的根在中序的位置 int rootPos = -1; for (int i = 0; i < in.length; i++) { if (in[i] == pre[0]) { rootPos = i; break; } } //构建下一次递归的数组 int[] nextPreLeft = Arrays.copyOfRange(pre, 1, rootPos + 1); int[] nextInLeft = Arrays.copyOfRange(in, 0, rootPos); int[] nextPreRight = Arrays.copyOfRange(pre, rootPos + 1, pre.length); int[] nextInRight = Arrays.copyOfRange(in, rootPos + 1, pre.length); root.left = reConstructBinaryTree(nextPreLeft, nextInLeft); root.right = reConstructBinaryTree(nextPreRight, nextInRight); return root; } }