solve problem Kth Largest Element In A Stream

Author: P-ppc

README.md

@@ -220,6 +220,7 @@ All solutions will be accepted!
 |558|[Quad Tree Intersection](https://leetcode-cn.com/problems/quad-tree-intersection/description/)|[java/py](./algorithms/QuadTreeIntersection)|Easy|
 |874|[Walking Robot Simulation](https://leetcode-cn.com/problems/walking-robot-simulation/description/)|[java/py/js](./algorithms/WalkingRobotSimulation)|Easy|
 |876|[Middle Of The Linked List](https://leetcode-cn.com/problems/middle-of-the-linked-list/description/)|[java/py/js](./algorithms/MiddleOfTheLinkedList)|Easy|
+|703|[Kth Largest Element In A Stream](https://leetcode-cn.com/problems/kth-largest-element-in-a-stream/description/KthLargestElementInAStream)|Easy|
 
 # Database
 |#|Title|Solution|Difficulty|

algorithms/KthLargestElementInAStream/README.md

@@ -0,0 +1,2 @@
+# Kth Largest Element In A Stream
+We can solve this problem by heapq in python or PriorityQueue in java

algorithms/KthLargestElementInAStream/Solution.java

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+class KthLargest {
+    int k;
+    PriorityQueue<Integer> queue;
+    
+    public KthLargest(int k, int[] nums) {
+        this.k  = k;
+        queue = new PriorityQueue<>();
+        if (nums.length <= k) {
+            for (int num : nums) queue.add(num);
+        } else {
+            for (int i = 0; i < k; i++) queue.add(nums[i]);
+            for (int i = k; i < nums.length; i++) {
+                if (queue.peek() < nums[i]) {
+                    queue.poll();
+                    queue.add(nums[i]);
+                }
+            }
+        }
+
+    }
+    
+    public int add(int val) {
+        if(queue.size() < k) {
+            queue.offer(val);
+        } else if(queue.peek() < val) {
+            queue.poll();
+            queue.offer(val);
+        }
+        return queue.peek();
+    }
+}
+
+/**
+ * Your KthLargest object will be instantiated and called as such:
+ * KthLargest obj = new KthLargest(k, nums);
+ * int param_1 = obj.add(val);
+ */

algorithms/KthLargestElementInAStream/solution.js

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+/**
+ * @param {number} k
+ * @param {number[]} nums
+ */
+var KthLargest = function(k, nums) {
+    let length = nums.length
+    this.heap = nums.sort((a, b) => a - b)
+    this.heap = this.heap.slice(length >= k ? length - k : 0)
+    this.length = k
+};
+
+/** 
+ * @param {number} val
+ * @return {number}
+ */
+KthLargest.prototype.add = function(val) {
+    let heapLength = this.heap.length
+    if (heapLength < this.length || this.heap[0] < val) {
+        let i = 0,
+            length = Math.min(this.length, heapLength)
+        while (i < length) {
+            if (this.heap[i] >= val) {
+                break
+            }
+            i++
+        }
+        this.heap.splice(i, 0, val)
+        if (heapLength === this.length) this.heap.shift()
+    }
+    return this.heap[0]
+};
+
+/** 
+ * Your KthLargest object will be instantiated and called as such:
+ * var obj = Object.create(KthLargest).createNew(k, nums)
+ * var param_1 = obj.add(val)
+ */

algorithms/KthLargestElementInAStream/solution.py

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+class KthLargest(object):
+
+    def __init__(self, k, nums):
+        """
+        :type k: int
+        :type nums: List[int]
+        """
+        self.pool = nums
+        self.size = len(self.pool)
+        self.k = k
+        heapq.heapify(self.pool)
+        while self.size > k:
+            heapq.heappop(self.pool)
+            self.size -= 1
+
+    def add(self, val):
+        """
+        :type val: int
+        :rtype: int
+        """
+        if self.size < self.k:
+            heapq.heappush(self.pool, val)
+            self.size += 1
+        elif val > self.pool[0]:
+            heapq.heapreplace(self.pool, val)
+        return self.pool[0]
+
+
+# Your KthLargest object will be instantiated and called as such:
+# obj = KthLargest(k, nums)
+# param_1 = obj.add(val)