2020-09-28

Author: Maserhe

700.二叉搜索树中的搜索.cpp

@@ -17,7 +17,22 @@
 class Solution {
 public:
     TreeNode* searchBST(TreeNode* root, int val) {
-
+        if (!root) return NULL;
+        stack<TreeNode * > st;
+        st.push(root);
+        while (st.size())
+        {
+            TreeNode * t = st.top();
+            st.pop();
+            if (t->val == val) return t;
+            else
+            {
+                if (t->left) st.push(t->left);
+                if (t->right) st.push(t->right);
+            }
+            
+        }
+        return NULL;
     }
 };
 // @lc code=end

703.数据流中的第k大元素.cpp

@@ -0,0 +1,30 @@
+/*
+ * @lc app=leetcode.cn id=703 lang=cpp
+ *
+ * [703] 数据流中的第K大元素
+ */
+
+// @lc code=start
+class KthLargest {
+public:
+    // 使用一个 multiset
+    multiset<int> st;
+    int k;
+    KthLargest(int k, vector<int>& nums) {
+        this->k = k;
+        st.insert(nums.begin(), nums.end());
+    }
+    int add(int val) {
+        st.insert(val);
+        while (st.size() > k) st.erase(st.begin());
+        return *st.begin();
+    }
+};
+
+/**
+ * Your KthLargest object will be instantiated and called as such:
+ * KthLargest* obj = new KthLargest(k, nums);
+ * int param_1 = obj->add(val);
+ */
+// @lc code=end
+

704.二分查找.cpp

@@ -0,0 +1,24 @@
+/*
+ * @lc app=leetcode.cn id=704 lang=cpp
+ *
+ * [704] 二分查找
+ */
+
+// @lc code=start
+class Solution {
+public:
+    int search(vector<int>& nums, int target) {
+        int l = 0, r = nums.size();
+        while (l < r)
+        {
+            int mid = l + r >> 1;
+            if (nums[mid] < target) l = mid + 1;
+            else r = mid;
+        }
+        if (l < 0 || l >= nums.size()) return -1;
+        if (nums[l] != target) return -1;
+        else return l;
+    }
+};
+// @lc code=end
+