杨辉三角打印

- (NSMutableArray*)printS:(NSInteger)n {
NSMutableArray* array = [NSMutableArray array];

if (n == 1) {
[array addObject:@(1)];
[array addObject:@(1)];

} else {
NSMutableArray* fowardArray = [self printS:n - 1];
for (int i = 0; i <= [fowardArray count]; i++) {
if (i == 0) {
[array addObject:fowardArray[0]];

} else if ( i == [fowardArray count]) {
[array addObject:[fowardArray lastObject]];

} else {
[array addObject:@([[fowardArray objectAtIndex:i-1] integerValue] + [[fowardArray objectAtIndex:i] integerValue])];
}
}
}

for (int i = 0; i < [array count]; i++) {
printf("  %ld", [[array objectAtIndex:i] integerValue]);
}
printf("\n");

return array;
}