题解 | #牛群的树形结构重建#

/**
 * struct TreeNode {
 *  int val;
 *  struct TreeNode *left;
 *  struct TreeNode *right;
 * };
 */
/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param inOrder int整型一维数组
 * @param inOrderLen int inOrder数组长度
 * @param postOrder int整型一维数组
 * @param postOrderLen int postOrder数组长度
 * @return TreeNode类
 */
struct TreeNode* buildTree(int* inOrder, int inOrderLen, int* postOrder,
                           int postOrderLen ) {
    if (inOrderLen == 0 || postOrderLen == 0) return NULL;
    int temp = postOrder[postOrderLen - 1];
    int i = 0, leftSize, rightSize;
    while (inOrder[i] != temp) i++;
    leftSize = i;
    rightSize = postOrderLen - i - 1;
    struct TreeNode* tree = malloc(sizeof(struct TreeNode));
    tree->val = temp;
    tree->left = buildTree(inOrder, leftSize, postOrder, leftSize);
    tree->right = buildTree(inOrder + leftSize + 1, rightSize, postOrder + leftSize,
                            rightSize);
    return tree;
}