RosettaCodeData/Task/Priority-queue/Objective-C/priority-queue.m

65 lines
1.9 KiB
Objective-C

#import <Foundation/Foundation.h>
const void *PQRetain(CFAllocatorRef allocator, const void *ptr) {
return (__bridge_retained const void *)(__bridge id)ptr;
}
void PQRelease(CFAllocatorRef allocator, const void *ptr) {
(void)(__bridge_transfer id)ptr;
}
CFComparisonResult PQCompare(const void *ptr1, const void *ptr2, void *unused) {
return [(__bridge id)ptr1 compare:(__bridge id)ptr2];
}
@interface Task : NSObject {
int priority;
NSString *name;
}
- (instancetype)initWithPriority:(int)p andName:(NSString *)n;
- (NSComparisonResult)compare:(Task *)other;
@end
@implementation Task
- (instancetype)initWithPriority:(int)p andName:(NSString *)n {
if ((self = [super init])) {
priority = p;
name = [n copy];
}
return self;
}
- (NSString *)description {
return [NSString stringWithFormat:@"%d, %@", priority, name];
}
- (NSComparisonResult)compare:(Task *)other {
if (priority == other->priority)
return NSOrderedSame;
else if (priority < other->priority)
return NSOrderedAscending;
else
return NSOrderedDescending;
}
@end
int main (int argc, const char *argv[]) {
@autoreleasepool {
CFBinaryHeapCallBacks callBacks = {0, PQRetain, PQRelease, NULL, PQCompare};
CFBinaryHeapRef pq = CFBinaryHeapCreate(NULL, 0, &callBacks, NULL);
CFBinaryHeapAddValue(pq, [[Task alloc] initWithPriority:3 andName:@"Clear drains"]);
CFBinaryHeapAddValue(pq, [[Task alloc] initWithPriority:4 andName:@"Feed cat"]);
CFBinaryHeapAddValue(pq, [[Task alloc] initWithPriority:5 andName:@"Make tea"]);
CFBinaryHeapAddValue(pq, [[Task alloc] initWithPriority:1 andName:@"Solve RC tasks"]);
CFBinaryHeapAddValue(pq, [[Task alloc] initWithPriority:2 andName:@"Tax return"]);
while (CFBinaryHeapGetCount(pq) != 0) {
Task *task = (id)CFBinaryHeapGetMinimum(pq);
NSLog(@"%@", task);
CFBinaryHeapRemoveMinimumValue(pq);
}
CFRelease(pq);
}
return 0;
}