tasks a-s

Task/Power-set/Objective-C/power-set.m

@@ -0,0 +1,17 @@
+#import <Foundation/Foundation.h>
+
++ (NSArray *)powerSetForArray:(NSArray *)array {
+	UInt32 subsetCount = 1 << array.count;
+	NSMutableArray *subsets = [NSMutableArray arrayWithCapacity:subsetCount];
+	for(int subsetIndex = 0; subsetIndex < subsetCount; subsetIndex++) {
+		NSMutableArray *subset = [[NSMutableArray alloc] init];
+		for (int itemIndex = 0; itemIndex < array.count; itemIndex++) {
+			if((subsetIndex >> itemIndex) & 0x1) {
+				[subset addObject:[array objectAtIndex:itemIndex]];
+			}
+		}		
+		[subsets addObject:subset];
+		[subset release];
+	}
+	return subsets;
+}