langs a-z

Task/Averages-Mode/Objective-C/averages-mode.m

@@ -0,0 +1,26 @@
+#import <Foundation/Foundation.h>
+
+@interface NSArray (Mode)
+- (NSArray *)mode;
+@end
+
+@implementation NSArray (Mode)
+- (NSArray *)mode {
+    NSCountedSet *seen = [NSCountedSet setWithArray:self];
+    int max = 0;
+    NSMutableArray *maxElems = [NSMutableArray array];
+    NSEnumerator *enm = [seen objectEnumerator];
+    id obj;
+    while( (obj = [enm nextObject]) ) {
+        int count = [seen countForObject:obj];
+        if (count > max) {
+            max = count;
+            [maxElems removeAllObjects];
+            [maxElems addObject:obj];
+        } else if (count == max) {
+            [maxElems addObject:obj];
+        }
+    }
+    return maxElems;
+}
+@end