public void set(int pos, int val){
			if(start == end && start == pos){
				minVal = maxVal = val;
			}else{
				int mid = (start+end)/2;
				if(pos<=mid)
					left.set(pos, val);
				else
					right.set(pos, val);
				minVal = Math.min(left.minVal, right.minVal);
				maxVal = Math.max(left.maxVal, right.maxVal);
			}
		}