✨ Day 21; Week 3 ✔️

Author: AkashRajpurohit

README.md

@@ -24,14 +24,15 @@
 6. [Sort List](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/560/week-2-october-8th-october-14th/3493/) ➡️ [CPP Solution](Week2/sortList.cpp)
 7. [House Robber II](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/560/week-2-october-8th-october-14th/3494/) ➡️ [CPP Solution](Week2/rob.cpp)
 
-## Week 3 🚧
+## Week 3 ✅
 
 1. [Rotate Array](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3496/) ➡️ [CPP Solution](Week3/rotate.cpp)
 2. [Search a 2D Matrix](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3497/) ➡️ [CPP Solution](Week3/searchMatrix.cpp)
 3. [Repeated DNA Sequences](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3498/) ➡️ [CPP Solution](Week3/findRepeatedDnaSequences.cpp)
 4. [Best Time to Buy and Sell Stock IV](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3499/) ➡️ [CPP Solution](Week3/maxProfit.cpp)
 5. [Minimum Domino Rotations For Equal Row](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3500/) ➡️ [CPP Solution](Week3/minDominoRotations.cpp)
 6. [Clone Graph](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3501/) ➡️ [CPP Solution](Week3/cloneGraph.cpp)
+7. [Asteroid Collision](https://leetcode.com/explore/challenge/card/october-leetcoding-challenge/561/week-3-october-15th-october-21st/3502/) ➡️ [CPP Solution](Week3/asteroidCollision.cpp)
 
 
 ## Week 4 🚧

Week3/asteroidCollision.cpp

@@ -0,0 +1,31 @@
+class Solution {
+public:
+    vector<int> asteroidCollision(vector<int>& asteroids) {
+        stack<int> s;
+        
+        for(int x: asteroids) {
+            if(x > 0) {
+                s.push(x);
+            } else {
+                while(!s.empty() && s.top() > 0 && s.top() < abs(x))
+                    s.pop();
+                
+                if(s.empty() || s.top() < 0)
+                    s.push(x);
+                else if(s.top() == abs(x))
+                    s.pop();
+            }
+        }
+        
+        vector<int> ans;
+        
+        while(!s.empty()) {
+            ans.push_back(s.top());
+            s.pop();
+        }
+        
+        reverse(ans.begin(), ans.end());
+        
+        return ans;
+    }
+};