create 0367-valid-perfect-square.cpp

cpp/0367-valid-perfect-square.cpp

@@ -0,0 +1,28 @@
+/*
+Approach: Binary search the number such that divind num by that number gives the number itself
+
+Time Complexity: log(n)
+Space Complexity: O(1)
+*/
+class Solution {
+public:
+    bool isPerfectSquare(int num) {
+        if(num ==1) {return true;}
+        int l = 0,r = num;
+        while(l<r){
+            int m = l + (r-l)/2;
+            float x = (float)num / (float)m;
+            if(x==m){
+                return true;
+            }
+            else if (x<m){
+                r = m;
+            }
+            else {
+                l = m +1;
+            }
+        }
+
+        return false;
+    }
+};