Project Euler : Objc - 5

E055.m

#import <Foundation/Foundation.h>

NSString *addString(NSString *a, NSString *b)
{
	NSString *result;
	@autoreleasepool{
		NSMutableString *sumString = [NSMutableString string];
		NSUInteger l1, l2;
		l1 = [a length] > [b length] ? [a length] : [b length];
		NSUInteger i,x,y,s,temp=0;
		for(i=0;i<l1;i++) {
			x = i >= [a length] ? 0 : [[a substringWithRange:NSMakeRange([a length] - i -1, 1)] intValue];
			y = i >= [b length] ? 0 : [[b substringWithRange:NSMakeRange([b length] - i -1, 1)] intValue];
			s = x + y + temp;
			if(s>9) {
				temp = s / 10;
				s = s % 10;
			} else {
				temp = 0;
			}
			[sumString insertString:[@(s) stringValue] atIndex:0];
		}
		if(temp) {
			[sumString insertString:[@(temp) stringValue] atIndex:0];
		}
		result = [sumString copy];
	}
	return [result autorelease];
}

NSString *reversedString(NSString *str)
{
	NSString *result;
	@autoreleasepool{
		NSMutableString *temp = [NSMutableString string];
		NSUInteger l = [str length], i;
		for(i=0;i<l;i++) {
			[temp appendString:[str substringWithRange:NSMakeRange(l-i-1, 1)]];
		}
		result = [temp copy];
	}
	return [result autorelease];
}

BOOL testNumber(int num)
{
	BOOL result = YES;
	@autoreleasepool{
		int count = 0;
		NSString *numString = (NSString*)[@(num) stringValue];

		while(count < 49) {
			numString = addString(numString, reversedString(numString));
			if([numString isEqualToString:reversedString(numString)]) {
				result = NO;
				break;
			}
			count ++;
		}
	}
	return result;
}


int main(int argc, char const *argv[])
{
	@autoreleasepool{
		int count = 0;
		int i=1;
		while(i<10001) {
			if(testNumber(i)) count++;
			i++;
		}
		NSLog(@"%d", count);
	}
	return 0;
}