sorting

问题 What is the best and most efficient way sorting an array of [String : String] by value? For example, let dicts = [["key": "4"], ["key": "4"], ["key": "3"], ["key":"1"]] then after sorting I want to have dicts = [["key": "1"], ["key": "3"], ["key": "4"], ["key":"4"]] 回答1: It's a little wordy, but it get you at good control of missing keys and non-int values. var array = [["key": "1"], ["key": "3"], ["key": "2"], ["key":"4"]] array.sort { (lhs, rhs) -> Bool in if let leftValue = lhs["key"], let

问题 Why is the worst case for insertion sort n^2? Can it be nlogn with binary search? Minimize the location search to log(n) and then use a low level function like memmove to minimize swaps? 回答1: Can it be nlogn with binary search? You will need to sort the array first to use binary search, as binary search is only possible in sorted array Edit Even if the first part of the array is sorted. The case now is that, you find the position to insert in logn steps. Then You actually need to insert the

问题 I have been having this problem lately when I get to the swapping part of this code, so what this code does is inputs an array and sorts it using the bubble sort method. The text file that reads this in has 10 numbers and names. Like this: John 1 Mark 2 Matthew 2 Luke 3 Issac 4 Kane 5 Ryan 7 Abel 2 Adam 9 Eve 10 However when it prints it out, it shows this: John 1 Mark 2 Matthew 2 Abel 2 Abel 3 Abel 4 Abel 5 Abel 7 Adam 9 Eve 10 Sorry, the question is why is it repeating Abel, and what can i

问题 i have a mongo php query with aggregate frame work, now i want to add sorting and select distinct criteria to that query, please not that my query is working perfectly without these two criterias, take a look $result = $collection->aggregate(array( array( '$match' => array( 'Details.Model' =>"AUDI", 'Details.Color' => "RED", "Category" =>"Car" ) ), array( '$unwind' => '$Details' ), array( '$match' => array( 'Details.Model' =>"AUDI", 'Details.Color' => "RED", "Category" =>"Car" ) ), array( '

问题 I know that there are many implementations of merge sort but this is one which I have read in the book "Introduction to algorithms". The following code is an implementation of merge sort which is not working correctly: #include <iostream> using namespace std; void merge(int*a, int p, int q, int r) { //function to merge two arrays int n1 = (q - p); // size of first sub array int n2 = (r - q); // size of second subarray int c[n1], d[n2]; for (int i = 0; i <= n1; i++) { c[i] = a[p + i]; } for

问题 I know that there are many implementations of merge sort but this is one which I have read in the book "Introduction to algorithms". The following code is an implementation of merge sort which is not working correctly: #include <iostream> using namespace std; void merge(int*a, int p, int q, int r) { //function to merge two arrays int n1 = (q - p); // size of first sub array int n2 = (r - q); // size of second subarray int c[n1], d[n2]; for (int i = 0; i <= n1; i++) { c[i] = a[p + i]; } for

问题 I'm trying to order elements of array1 based on the sorted order of array2. In my case, both array1 and array2 are members of the same class and they are public. I'm trying to use a nested class within my class to write the compare() function of std::sort as a functor, so that the nested class can access array2. Here is the code: #include <iostream> #include <algorithm> using namespace std; class sort_test { public: sort_test() { //some initialization } int array1[10]; int array2[10]; int

问题 I wonder how Python decides the order between two items that would be in a tie based on some specified key of a sort. For example, given: l = [[1, 2, 3], [1, 2], [1], [2, 3, 4], [1, 2, 4, 5]] , how does Python order [1, 2, 3] and [2, 3, 4] in this sort: sorted(l, key=lambda i: len(i), reverse=True) Does it keep the original (relative) order between items in a tie? Or does it order them randomly? 回答1: Also in wiki: Starting with Python 2.2, sorts are guaranteed to be stable. That means that

问题 I wonder how Python decides the order between two items that would be in a tie based on some specified key of a sort. For example, given: l = [[1, 2, 3], [1, 2], [1], [2, 3, 4], [1, 2, 4, 5]] , how does Python order [1, 2, 3] and [2, 3, 4] in this sort: sorted(l, key=lambda i: len(i), reverse=True) Does it keep the original (relative) order between items in a tie? Or does it order them randomly? 回答1: Also in wiki: Starting with Python 2.2, sorts are guaranteed to be stable. That means that

问题 I want to modify this algorithm so that it can find values within an array which has been sorted in descending order. This currently only works for ascending. public static int interpo(double[] array, double key, int order) { int low = 0, high = array.Length - 1; int pos = 0; int count = 0; while ((low <= high) && (key >= array[low]) && (key <= array[high])) { count++; pos = Convert.ToInt32(low + (high - low) / (array[high] - array[low]) * (key - array[low])); if (array[pos] == key) { //