在stackoverflow上似乎有很多关于这个主题的Q/A,但我似乎无法在任何地方找到确切的答案.
是)我有的:
我有公司和人员模型:
var mongoose = require('mongoose');
var PersonSchema = new mongoose.Schema{
name: String,
lastname: String};
// company has a reference to Person
var CompanySchema = new mongoose.Schema{
name: String,
founder: {type:Schema.ObjectId, ref:Person}};
我需要的:
找到所有姓氏为"Robertson"的人成立的公司
我尝试了什么:
Company.find({'founder.id': 'Robertson'}, function(err, companies){
console.log(companies); // getting an empty array
});
然后我认为Person不是嵌入式的,而是引用的,所以我使用populate来填充创始人Person,然后尝试使用find和'Robertson'lastname
// 1. retrieve all companies
// 2. populate their founders
// 3. find 'Robertson' lastname in populated Companies
Company.find({}).populate('founder')
.find({'founder.lastname': 'Robertson'})
.exec(function(err, companies) {
console.log(companies); // getting an empty array again
}); …我在俄罗斯的一个编程论坛上遇到过这个问题,但还没有提出一个优雅的解决方案.
问题:
你有一个N正整数的数组,你需要将它分成M个连续的段,这样最大的段的总和是最小的可能值.按段的总数,我的意思是所有整数的总和.换句话说,我想要一个平衡良好的数组分割,你不希望单个分段过大.
例:
数组:[4,7,12,5,3,16]
M = 3,意味着我需要将我的数组分成3个子阵列.
解决方案是:[4,7] [12,5] [3,16],以便最大的段是[3,16] = 19,并且没有其他的分段变体可以产生总数较小的最大段.
另一个例子:
解决方案:[3,13,5] [7,18] [8] [20,1],"最胖"段是[7,18] = 25(纠正我,如果我错了,我编的是这个例子)
我有一种感觉,这是一些经典的CS /数学问题,可能有一些着名人物的名字,如Dijkstra的问题. - 有没有任何已知的解决方案？- 如果没有,你能否提出除暴力强迫之外的其他解决方案,据我所知,时间复杂度,指数.(N ^ M,更具体).
提前谢谢,stackoverflowers.
我想在导航栏中添加一个"书签"按钮作为rightBarButtonItem
- (void)viewDidLoad
{
[super viewDidLoad];
// Add bookmark button
UIBarButtonItem *bookmarkBarButton = [[UIBarButtonItem alloc] initWithTitle:@"" style:UIBarButtonItemStyleBordered target:self action:@selector(bookmark:)];
[bookmarkBarButton setImage:[UIImage imageNamed:@"greyBookmark.png"]];
[self.navigationItem setRightBarButtonItem:bookmarkBarButton];
bookmarkBarButton.tintColor = [UIColor colorWithRed:0.4 green:0.4 blue:0.4 alpha:0.9f];
b_bookmarked = false;
}
// Will call this method when the bookmark button is pressed
- (IBAction)bookmark:(id)sender
{
// Toggle color of bookmark icon on button
if ( (b_bookmarked = !b_bookmarked) )
{
[self.navigationItem.rightBarButtonItem setImage:[UIImage imageNamed:@"blueBookmark.png"]];
}
else
{
[self.navigationItem.rightBarButtonItem setImage:[UIImage imageNamed:@"greyBookmark.png"]];
}
// Save bookmark
}
greyBookmark.png和blueBookmark.png都有10x26大小.视图出现时,按钮看起来变窄.但是当我单击此按钮时,按钮会变宽,但图像仍然会发生变化.在bookmark:方法中调用setImage方法时,宽度会更改(恢复为默认大小).我试图通过调用[navigationItem.rightBarButtonItem setWidth:]显式设置宽度 …
我有一个包含大量文本的视图,所以我希望允许用户在单击时隐藏statusBar + navigationBar.我真的很喜欢图片应用程序中的隐藏风格,其中statusBar和navigationBar隐藏在一起(不滑动,只是淡出),有一些animationDuration,所以我尝试做类似的事情.这是我在touchesDidBegan方法中所做的:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackTranslucent];
[UIView setAnimationDuration:0.5];
[UIView beginAnimations:@"" context:nil];
[[UIApplication sharedApplication] setStatusBarHidden:!([UIApplication sharedApplication].statusBarHidden) withAnimation:UIStatusBarAnimationNone];
[self.navigationController setNavigationBarHidden:(!self.navigationController.navigationBarHidden) animated:NO];
[UIView commitAnimations];
self.navigationController.navigationBar.translucent = !self.navigationController.navigationBar.translucent; // this is needed to make bars appear on top of my view.
}
但这并不能同时隐藏条形图.它让它们向下滑动.它与上述方法的版本具有相同的效果:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleBlackTranslucent];
// deleted UIView animation, changed animation type to "slide"
[[UIApplication sharedApplication] setStatusBarHidden:!([UIApplication sharedApplication].statusBarHidden) withAnimation:UIStatusBarAnimationSlide];
// enabled animation for navBar
[self.navigationController setNavigationBarHidden:(!self.navigationController.navigationBarHidden) animated:YES];
self.navigationController.navigationBar.translucent = …