Merge branch 'master' of https://github.com/daiwb/Algorithm

daiwb · daiwb · commit dd588086fa0e · 2014-06-01T18:47:53.000-07:00
diff --git a/LeetCode/sortedListToBST.cpp b/LeetCode/sortedListToBST.cpp
@@ -0,0 +1,41 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+/**
+ * Definition for binary tree
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    TreeNode *doit(ListNode* &head, int st, int ed) {
+        if (st > ed) return NULL;
+        int md = (st + ed) / 2;
+        TreeNode *lTree = doit(head, st, md - 1);
+        TreeNode *par = new TreeNode(head->val);
+        head = head->next;
+        TreeNode *rTree = doit(head, md + 1, ed);
+        par->left = lTree;
+        par->right = rTree;
+        return par;
+    }
+    TreeNode *sortedListToBST(ListNode *head) {
+        if (head == NULL) return NULL;
+        int len = 0;
+        ListNode *t = head;
+        while (t) {
+            ++len;
+            t = t->next;
+        }
+        return doit(head, 1, len);
+    }
+};
