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invert-binary-tree.cpp

@@ -0,0 +1,21 @@
+/** 
+ * Definition for a binary tree node.  
+ * struct TreeNode { 
+ *     int val; 
+ *     TreeNode *left; 
+ *     TreeNode *right; 
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} 
+ * }; 
+ */ 
+class Solution { 
+public: 
+    TreeNode* invertTree(TreeNode* root) {
+        if (root == NULL) {
+            return root;
+        }
+        swap(root->left, root->right);
+        invertTree(root->left);
+        invertTree(root->right);
+        return root;
+    } 
+};

power-of-two.cpp

@@ -0,0 +1,10 @@
+class Solution { 
+public: 
+    bool isPowerOfTwo(int n) { 
+        if (n <= 0) {
+            return false;
+        }
+        n &= (n - 1);
+        return n == 0;
+    } 
+};

readme.md

@@ -1,3 +1,3 @@
 ###__Greatness from Basis comes__    
-Finished 185/218       
+Finished 188/219       
 Reetsee.Xu last updated on 2015.07.11               

summary-ranges.cpp

@@ -0,0 +1,30 @@
+class Solution { 
+public: 
+    vector<string> summaryRanges(vector<int>& nums) { 
+        vector<string> range_vector;
+        size_t nums_size = nums.size();
+        if (nums_size == 0) {
+            return range_vector;
+        }
+
+        int last_num = nums[0];
+        for (size_t i = 1; i < nums_size; ++i) {
+            if (nums[i] != nums[i-1] + 1) {
+                addRange(range_vector, last_num, nums[i-1]);
+                last_num = nums[i];
+            }
+        }
+        addRange(range_vector, last_num, nums.back());
+        return range_vector;
+    } 
+
+    void addRange(vector<string>& range_vector, int left, int right) {
+        char range[32];
+        if (left == right) {
+            snprintf(range, sizeof(range), "%d", left);
+        } else {
+            snprintf(range, sizeof(range), "%d->%d", left, right);
+        }
+        range_vector.push_back(range);
+    }
+};