If there are 200 lions in the park, which is twice the number of leopards in the park, there are 200/2 = <<200/2=100>>100 leopards in the park.
The total population of lions and leopards in the park is 200 lions + 100 leopards = <<200+100=300>>300
The number of elephants in the park is 1/2 the total population of lions and leopards; thus, there are 300/2 = <<300/2=150>>150 elephants in the park.
There are a total of 150+300 = <<150+300=450>>450 animals in the park.
#### 450