Commit 80c4ffb

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Merge pull request #8 from joney000/priority_queue

add priority queue

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	`1`	`+class Solution {`
	`2`	`+`
	`3`	`+ class Point{`
	`4`	`+ int x, y;`
	`5`	`+ int distance;`
	`6`	`+ public Point(int x, int y){`
	`7`	`+ this.x = x;`
	`8`	`+ this.y = y;`
	`9`	`+ this.distance = x * x + y * y;`
	`10`	`+ }`
	`11`	`+`
	`12`	`+ }`
	`13`	`+`
	`14`	`+ // returns the K Closest points from origin (0, 0)`
	`15`	`+ // Time: O(n log k), space: O(k)`
	`16`	`+ public int[][] kClosest(int[][] points, int k) {`
	`17`	`+ if(points.length == 0 \|\| k > points.length){`
	`18`	`+ return null;`
	`19`	`+ }`
	`20`	`+ int numPoints = points.length;`
	`21`	`+ PriorityQueue<Point> pQueue = new PriorityQueue<Point>(k + 1, (a,b) -> (b.distance - a.distance)); // max elem on top`
	`22`	`+ for(int[] point: points){`
	`23`	`+ pQueue.add(new Point(point[0], point[1]));`
	`24`	`+ if(pQueue.size() > k){`
	`25`	`+ pQueue.poll();`
	`26`	`+ }`
	`27`	`+ }`
	`28`	`+ int[][] sortedElements = new int[k][2];`
	`29`	`+ for(int pos = k - 1; pos >= 0; pos--){`
	`30`	`+ Point point = (Point)pQueue.poll();`
	`31`	`+ sortedElements[pos][0] = point.x;`
	`32`	`+ sortedElements[pos][1] = point.y;`
	`33`	`+ }`
	`34`	`+ return sortedElements;`
	`35`	`+ }`
	`36`	`+}`

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`@@ -40,6 +40,7 @@ In This Repository, I have written some of the important Algorithms and Data Str`
`40`	`40`	`\| [Kth Order Statics](https://github.com/joney000/Java-Competitive-Programming/blob/master/Algorithms/kthOrderStatics.java)\|O(N), O(N) \| K’th Smallest/Largest Element in Unsorted Array`
`41`	`41`	`\| [Trie / Prefix Tree](https://github.com/joney000/Java-Competitive-Programming/blob/master/Algorithms/Trie.java)\| O(N * L), O(N * L)\| if there are N strings of L size, per query time(Prefix information) = O(L)`
`42`	`42`	`\| [LIS - Longest Increasing Subsequence](https://github.com/joney000/Java-Competitive-Programming/blob/master/Algorithms/LIS_nLOGn.java)\| O(N * log(N)), O(N)`
	`43`	`+\| [Priority Queue](https://github.com/joney000/Java-Competitive-Programming/blob/master/Algorithms/PriorityQueue.java)\| O(log(N)), O(N) \| N = no of objects in the queue. peek: O(1), poll/add: O(log n)`
`43`	`44`
`44`	`45`	`## Contributions`
`45`	`46`

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