Pseudo code for space-efficiently saving number ranges.

pseudo

node::insert(int value) {

   // Value falls in range
   if(value >= this.min && value <= this.max) {
       
   } 
   
   // Extend range
   if(value == this.min - 1) {
       this.min = value;
       
       if(this.right.max == value) {
           // Merge right with this
       }
   }
   
   // Extend range
   if(value == this.max + 1) {
       this.max = value;
       
       if(this.left.min == value) {
           // Merge left with this
       }
   }
   
   
   if(value > this.max) {
       this.left.insert(value);
   }

   if(value < this.min) {
       this.right.insert(value);
   }
}