queue Algorithm
In computer science, a priority queue is an abstract data type like to regular queue or stack data structure in which each component additionally has a" priority" associated with it. In a priority queue, an component with high priority is served before an component with low priority.
// Queue ADT implementation ... COMP2521
#include <stdlib.h>
#include <assert.h>
#include "queue.h"
typedef struct node {
int data;
struct node *next;
} NodeT;
typedef struct QueueRep {
int length;
NodeT *head;
NodeT *tail;
} QueueRep;
// set up empty queue
queue newQueue() {
queue Q = malloc(sizeof(QueueRep));
Q->length = 0;
Q->head = NULL;
Q->tail = NULL;
return Q;
}
// remove unwanted queue
void dropQueue(queue Q) {
NodeT *curr = Q->head;
while (curr != NULL) {
NodeT *temp = curr->next;
free(curr);
curr = temp;
}
free(Q);
}
// check whether queue is empty
int QueueIsEmpty(queue Q) {
return (Q->length == 0);
}
// insert an int at end of queue
void QueueEnqueue(queue Q, int v) {
NodeT *new = malloc(sizeof(NodeT));
assert(new != NULL);
new->data = v;
new->next = NULL;
if (Q->tail != NULL) {
Q->tail->next = new;
Q->tail = new;
} else {
Q->head = new;
Q->tail = new;
}
Q->length++;
}
// remove int from front of queue
int QueueDequeue(queue Q) {
assert(Q->length > 0);
NodeT *p = Q->head;
Q->head = Q->head->next;
if (Q->head == NULL) {
Q->tail = NULL;
}
Q->length--;
int d = p->data;
free(p);
return d;
}
// By
// .----------------. .----------------. .----------------. .-----------------. .----------------. .----------------.
// | .--------------. || .--------------. || .--------------. || .--------------. | | .--------------. || .--------------. |
// | | _________ | || | _____ _____ | || | __ | || | ____ _____ | | | | ____ ____ | || | ____ | |
// | | | _ _ | | || ||_ _||_ _|| || | / \ | || ||_ \|_ _| | | | | |_ || _| | || | .' `. | |
// | | |_/ | | \_| | || | | | | | | || | / /\ \ | || | | \ | | | | | | | |__| | | || | / .--. \ | |
// | | | | | || | | ' ' | | || | / ____ \ | || | | |\ \| | | | | | | __ | | || | | | | | | |
// | | _| |_ | || | \ `--' / | || | _/ / \ \_ | || | _| |_\ |_ | | | | _| | | |_ | || | \ `--' / | |
// | | |_____| | || | `.__.' | || ||____| |____|| || ||_____|\____| | | | | |____||____| | || | `.____.' | |
// | | | || | | || | | || | | | | | | || | | |
// | '--------------' || '--------------' || '--------------' || '--------------' | | '--------------' || '--------------' |
// '----------------' '----------------' '----------------' '----------------' '----------------' '----------------'
// Email : z5261243@unsw.edu.au
// hhoanhtuann@gmail.com
