Initial data commit

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

@@ -0,0 +1,64 @@
+#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;
+}