Added Ugly Numbers implementation

others/ugly_numbers.cpp

@@ -0,0 +1,76 @@
+// Ugly numbers are those number whose prime factors are 2, 3 or 5. 
+// From 1 to 15, there are 11 ugly numbers 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15. 
+// The numbers 7, 11, 13 are not ugly because they are prime.
+
+#include<iostream>
+using namespace std;
+
+int min(int x, int y, int z) {            //find smallest among three numbers
+   if(x < y) {
+      if(x < z)
+         return (x);
+      else 
+         return (z);
+   }else {
+      if(y < z)
+         return (y);
+      else
+         return (z);
+   }
+}
+
+int getUglyNum( long n) {
+    long uglyNum[n];          // To store ugly numbers
+    int i2 = 0, i3 = 0, i5 = 0;
+
+   //find next multiple as 1*2, 1*3, 1*5
+
+   int next2mul = 2;
+   int next3mul = 3;
+   int next5mul = 5;
+   int next = 1;              //initially the ugly number is 1
+
+   uglyNum[0] = 1;
+
+   for (int i=1; i<n; i++) {
+      next = (min(next2mul, next3mul, next5mul));       //find next ugly number
+      uglyNum[i] = next;
+
+      if (next == next2mul) {
+         i2++;             //increase iterator of ugly numbers whose factor is 2
+         next2mul = (uglyNum[i2]*2);
+      }
+
+      if (next == next3mul) {
+         i3++;             //increase iterator of ugly numbers whose factor is 3
+         next3mul = (uglyNum[i3]*3);
+      }
+
+      if (next == next5mul) {
+         i5++;              //increase iterator of ugly numbers whose factor is 5
+         next5mul =( uglyNum[i5]*5);
+      }
+   }
+   return (next);        //the nth ugly number
+}
+
+int main()
+{
+	int T=0,r=0;
+	cin>>T;
+	r=T;
+	unsigned long  arr[T]={};
+	while(T!=0)
+	{
+	    long n=0;
+	    cin>>n;
+	    
+	    arr[T]= (getUglyNum(n));
+	T--;
+	}
+	for(int i=r;i>0;i--)
+	{
+		cout<<arr[i]<<"\n";
+	}
+	return 0;
+}