algo_021.md (427B)
1 # algo_021 2 3 ### Problem Statement 4 5 > Write an algorithm to insert a node at the beginning of a double linked list. 6 7 ## Algorithm 8 ``` 9 procedure insert_begin(dl, val) 10 begin 11 ptr ← getNode(); 12 info(ptr) ← val; 13 prev(ptr) ← NULL; 14 next(ptr) ← NULL; 15 if(dl = NULL) 16 dl ← ptr; 17 else 18 next(ptr) ← dl; 19 prev(dl) ← ptr; 20 dl ← ptr; 21 endif 22 return(dl); 23 end procedure 24 ```