Merge pull request #1 from gantavya12/patch-1

Create Leetcode-The-Skyline-Problem.cpp

Author: gantavyamalviya

CPP/Leetcode-The-Skyline-Problem.cpp

@@ -0,0 +1,39 @@
+class Solution {
+public:
+ vector<vector<int>> getSkyline(vector<vector<int>>& buildings) {
+ vector<vector<int>> ans;
+ multiset<int> pq{0};
+
+ vector<pair<int, int>> points;
+
+ for(auto b: buildings){
+ points.push_back({b[0], -b[2]});
+ points.push_back({b[1], b[2]});
+ }
+
+ sort(points.begin(), points.end());
+
+ int ongoingHeight = 0;
+
+ // points.first = x coordinate, points.second = height
+ for(int i = 0; i < points.size(); i++){
+ int currentPoint = points[i].first;
+ int heightAtCurrentPoint = points[i].second;
+
+ if(heightAtCurrentPoint < 0){
+ pq.insert(-heightAtCurrentPoint);
+ } else {
+ pq.erase(pq.find(heightAtCurrentPoint));
+ }
+
+ // after inserting/removing heightAtI, if there's a change
+ auto pqTop = *pq.rbegin();
+ if(ongoingHeight != pqTop){
+ ongoingHeight = pqTop;
+ ans.push_back({currentPoint, ongoingHeight});
+ }
+ }
+
+ return ans;
+ }
+};