reverse

问题 I have a queue with some numbers for example 5,6,7,8 is in queue, 5 is q->front and 8 is q->rear.. Can I reverse them in queue but without using stacks? 回答1: Of course! But it won't be as efficient. Using a stack: O(N) time. O(1) memory. Using an associative array: O(N) time. O(1) memory. Using a fixed-size array: O(N) time. O(N) memory. Using an extendable array: O(N) time. O(N) memory. Using a queue: O(N^2) time. O(1) memory. Using an associative array will use more time than using a stack,

问题 I have a queue with some numbers for example 5,6,7,8 is in queue, 5 is q->front and 8 is q->rear.. Can I reverse them in queue but without using stacks? 回答1: Of course! But it won't be as efficient. Using a stack: O(N) time. O(1) memory. Using an associative array: O(N) time. O(1) memory. Using a fixed-size array: O(N) time. O(N) memory. Using an extendable array: O(N) time. O(N) memory. Using a queue: O(N^2) time. O(1) memory. Using an associative array will use more time than using a stack,

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 years ago . Once my new version is proved and release if I want to roll back, is itunes have a functionality where it will restore to the previous version or I should resubmit the old version? Thanks 回答1: Once an app version is approved and released to the App Store, there is no way to remove that version. If you were still

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 years ago . Once my new version is proved and release if I want to roll back, is itunes have a functionality where it will restore to the previous version or I should resubmit the old version? Thanks 回答1: Once an app version is approved and released to the App Store, there is no way to remove that version. If you were still

问题 I have setup a reverse proxy for the website, and now I want to proxy my game server aswell with the ports stated below, but I realy can't find anywhere how to perform this. Does anyone have an idea? I would like to do this if possible on apache. Am running on ubuntu. RDP TCP Port: 3389 MSSQL TCP Port: 1143 TEAMSPEAK UDP Port: 9987 TCP Port: 9987 TCP Port: 10011 TCP Port: 30033 LOGIN SERVER TCP Port: 15001 TCP Port: 15100 GAMESERVER TCP Port: 15221 FTP 21 回答1: Apache is not an ideal tool for

问题 I would like a command line incantation to reverse the field order of arbritrary length text records. Solutions provided in Rearrange columns using cut and Elegant way to reverse column order don't solve this issue since they assume a fixed amount of fields, though maybe they would with minor changes. Sort of like the tac command that exhibits reverse cat functionality. I'd like what the ohce command would do (if it existed) to reverse echo functinality. For example: a b c d e f g h i Should

问题 My recursion skill is pretty rusty. I've been thinking about this problem and searched the forum for a long time but still cannot understand. Right now I'm looking at the recursively reverse a linked list code from Stanford CS ed library. #include <stdio.h> struct Node { int x; struct Node *next; }; void Reverse(struct Node ** headRef){ struct Node* first; struct Node* rest; if(*headRef==NULL) return; first= *headRef; rest= first->next; if(rest==NULL) return; Reverse(&rest); printf("Rest%d\n"

问题 I've come up with the following solution in C for reversing a string: #include <stdio.h> void reverse(char * head); void main() { char * s = "sample text"; reverse(s); printf("%s", s); } void reverse(char * head) { char * end = head; char tmp; if (!head || !(*head)) return; while(*end) ++end; --end; while (head < end) { tmp = *head; *head++ = *end; *end-- = tmp; } } However my solution is segfaulting. According to GDB, the offending line is the following: *head++ = *end; The line segfaults on

问题 Is it possible to have a foreach statement that will traverse through a Collections object in reverse order? If not a foreach statement, is there another way? 回答1: You can use a normal for loop backwards, like this: for (int i = collection.Count - 1; i >= 0 ; i--) { var current = collection[i]; //Do things } You can also use LINQ: foreach(var current in collection.Reverse()) { //Do things } However, the normal for loop will probably be a little bit faster. 回答2: You could just call Reverse()

问题 What is the best way to "slice" an NSArray from the end, rather than the beginning, of the array (for example, finding the subarray containing the last few elements of a NSArray of unknown length)? In Python, you can use negative indices to accomplish this, e.g.: new_list = old_list[-5:-3] What's the most natural way to do this in Objective-C? 回答1: There's nothing to match Python's nice syntax for this, but you could do: NSUInteger count = [myArray count]; NSArray * slice = [myArray