Completed CP-1

Problem1.cpp

@@ -1 +1,20 @@
+// MISSING ELEMENT IN A SORTED ARRAY
+
+int missingNumber(vector<int>& nums) {
+    int low = 0, high = nums.size() - 1;
+
+    while (low <= high) {
+        int mid = low + (high - low) / 2;
+
+        if (nums[mid] == mid + 1)// check if the index and the element are right or not for mid
+        // if mid is at the right position it means,left half of mid sorted and theres nothing missing
+            low = mid + 1;//hence we increment low by mid + 1
+        else
+            high = mid - 1;// if mid index and mid element dont pass the if condition
+    }
+
+    return low + 1;// after repetitive looping we will eventually come out of the loop when low>high 
+    // in that case we can find the missing by returning low + 1
+    // return "low" if you want the position where the element is supposed to be in
+}
 

Problem2.cpp

@@ -1 +1,49 @@
+//DESIGN A MIN HEAP
+
+class minHeap{
+    vector<int> h;
+
+    public:
+     minHeap() {}
+
+    int getMin(){
+        return h[0];
+    }
+
+    void insert(int x){
+        h.push_back(x);
+        int i = h.size() - 1;
+
+        while(i > 0 && (i-1)/2 > i){
+            swap(h[(i-1)/2],h[i]); 
+            i = i - 1/2;//root
+        }
+    }
+
+    int extractMin(){
+        int minVal = h[0];
+        h[0] = h.push_back();
+        h.pop_back();
+
+        int i = 0;
+        int n = h.size();
+
+        while(true){
+            int l = 2*i + 1;//left
+            int r = 2*i + 2;//right
+            int s = i;
+
+            if (l < n && h[l] < h[s]) s = l;//left child exists
+
+            if (r < n && h[r] < h[s]) s = r;//right child exists
+
+            if (s == i) break;//parent is already smaller than both children
+
+            swap(h[i], h[s]);
+
+            i = s;
+        }
+        return minVal;
+    }
+};