Data commit

Task/Binary-search/Objective-C/binary-search-1.m

@@ -0,0 +1,41 @@
+#import <Foundation/Foundation.h>
+
+@interface NSArray (BinarySearch)
+// Requires all elements of this array to implement a -compare: method which
+// returns a NSComparisonResult for comparison.
+// Returns NSNotFound when not found
+- (NSInteger) binarySearch:(id)key;
+@end
+
+@implementation NSArray (BinarySearch)
+- (NSInteger) binarySearch:(id)key {
+  NSInteger lo = 0;
+  NSInteger hi = [self count] - 1;
+  while (lo <= hi) {
+    NSInteger mid = lo + (hi - lo) / 2;
+    id midVal = self[mid];
+    switch ([midVal compare:key]) {
+    case NSOrderedAscending:
+      lo = mid + 1;
+      break;
+    case NSOrderedDescending:
+      hi = mid - 1;
+      break;
+    case NSOrderedSame:
+      return mid;
+    }
+  }
+  return NSNotFound;
+}
+@end
+
+int main()
+{
+  @autoreleasepool {
+
+    NSArray *a = @[@1, @3, @4, @5, @6, @7, @8, @9, @10];
+    NSLog(@"6 is at position %d", [a binarySearch:@6]); // prints 4
+
+  }
+  return 0;
+}

Task/Binary-search/Objective-C/binary-search-2.m

@@ -0,0 +1,38 @@
+#import <Foundation/Foundation.h>
+
+@interface NSArray (BinarySearchRecursive)
+// Requires all elements of this array to implement a -compare: method which
+// returns a NSComparisonResult for comparison.
+// Returns NSNotFound when not found
+- (NSInteger) binarySearch:(id)key inRange:(NSRange)range;
+@end
+
+@implementation NSArray (BinarySearchRecursive)
+- (NSInteger) binarySearch:(id)key inRange:(NSRange)range {
+  if (range.length == 0)
+    return NSNotFound;
+  NSInteger mid = range.location + range.length / 2;
+  id midVal = self[mid];
+  switch ([midVal compare:key]) {
+  case NSOrderedAscending:
+    return [self binarySearch:key
+                      inRange:NSMakeRange(mid + 1, NSMaxRange(range) - (mid + 1))];
+  case NSOrderedDescending:
+    return [self binarySearch:key
+                      inRange:NSMakeRange(range.location, mid - range.location)];
+  default:
+    return mid;
+  }
+}
+@end
+
+int main()
+{
+  @autoreleasepool {
+
+    NSArray *a = @[@1, @3, @4, @5, @6, @7, @8, @9, @10];
+    NSLog(@"6 is at position %d", [a binarySearch:@6]); // prints 4
+
+  }
+  return 0;
+}

Task/Binary-search/Objective-C/binary-search-3.m

@@ -0,0 +1,15 @@
+#import <Foundation/Foundation.h>
+
+int main()
+{
+  @autoreleasepool {
+
+    NSArray *a = @[@1, @3, @4, @5, @6, @7, @8, @9, @10];
+    NSLog(@"6 is at position %lu", [a indexOfObject:@6
+                                      inSortedRange:NSMakeRange(0, [a count])
+                                            options:0
+                                    usingComparator:^(id x, id y){ return [x compare: y]; }]); // prints 4
+
+  }
+  return 0;
+}

Task/Binary-search/Objective-C/binary-search-4.m

@@ -0,0 +1,19 @@
+#import <Foundation/Foundation.h>
+
+CFComparisonResult myComparator(const void *x, const void *y, void *context) {
+  return [(__bridge id)x compare:(__bridge id)y];
+}
+
+int main(int argc, const char *argv[]) {
+  @autoreleasepool {
+
+    NSArray *a = @[@1, @3, @4, @5, @6, @7, @8, @9, @10];
+    NSLog(@"6 is at position %ld", CFArrayBSearchValues((__bridge CFArrayRef)a,
+                                                        CFRangeMake(0, [a count]),
+                                                        (__bridge const void *)@6,
+                                                        myComparator,
+                                                        NULL)); // prints 4
+
+  }
+  return 0;
+}