wrote a C program that performs state-space search for the 15-Puzzle similar in principle to those used in game engines. This search consists of a main loop that operates on two major lists open and closed and a small list, successors. Write a C program that performs A* search using open, closed, succ, expand(node), filter(succ, list), merge(lst1,lst2). Write the main loop and merge(). DO NOT write filter() and expand(). Again, use the same structure used in the homework. Assume the values used for node selection are computed and insertion functions listed

Problem 3  In HW6, you wrote a C program that performs state-space search for the 15-Puzzle similar in principle to those used in game engines. This search consists of a main loop that operates on two major lists open and 
closed and a small list, successors. Write a C program that performs A* search using open, closed, succ, expand(node), filter(succ, list), merge(lst1,lst2). Write the main loop and merge(). DO NOT write filter() and expand(). Again, use the same 
structure used in the homework. Assume the values used for node selection are computed and insertion functions listed 
below are available:
struct node *insert_by_h(node,lst),*insert_by_g(node,lst),*insert_by_f(node,lst); /* insert a node to list */
struct node {
 int loc[N+1][N]; /* the last row holds the three values used for node selection */
 struct node *next;
} *start,*goal;
struct node *initialize(),*expand(),*merge(),*filter();
int main(int argc,char **argv) {
struct node *tsucc,*csucc,*copen,*topen,*open,*closed,*succ;
open=closed=succ=NULL;
start=initialize(argc,argv); /* init initial and goal states */
open=start; 

code here 

}
/* you may use any and all of the insert functons listed above */
struct node *merge(struct node *succ,struct node *open,int flag) {
struct node *csucc,*copen;

code here 

return open;
}