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Objective-C实现丑数（Ugly Number）算法

丑数是指仅由质因数2、3和5组成的正整数。丑数序列包括：1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 25, 27, 30, 32, 33, 34, 35, 36, 40, 42, 45, 48, 50, 54, 60, 64, 65, 66, 68, 70, 72, 75, 76, 78, 80等。

以下是使用Objective-C通过动态规划生成丑数的完整代码示例：

代码示例：UglyNumberGenerator.m

@interface UglyNumberGenerator : NSObject

@property (nonatomic, strong) NSArray *uglyNumbers;

• (NSArray *)generateUglyNumbersUpTo:(int)number;

  if (number <= 1) {return [NSArray array];}

  self.uglyNumbers = [self generateUglyNumbersUpTo:2];NSMutableArray *result = [self.uglyNumbers mutableCopy];

  for (int i = 3; i <= number; i++) {if ([self isUgly:i]) {[result addObject:i];}}

  return [result sortedArray];}

• (BOOL)isUgly:(int)n {return ([n % 2 == 0] || [n % 3 == 0] || [n % 5 == 0]) && ![self isUgly:[n / 2] || [n / 3] || [n / 5]];}

• (NSArray *)generateUglyNumbers {return [self generateUglyNumbersUpTo:75];}

• (void)printUglyNumbers {NSLog(@"丑数序列：%@", [self generateUglyNumbers]);}

• (void)test {[self printUglyNumbers];}

@end

代码解释：

通过上述代码，可以轻松生成丑数序列，适用于需要用丑数的应用场景。

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