permutation

来源： https://stackoverflow.com/questions/64237931/for-repeated-rows-in-dataframe-column-of-nested-lists-group-and-replace-other-c

来源： https://stackoverflow.com/questions/49478238/permutation-iterator-in-java

来源： https://stackoverflow.com/questions/63807402/generate-all-combination-and-permutation-of-supplied-word

来源： https://stackoverflow.com/questions/5602488/random-picks-from-permutation-generator

问题 I have a c++ vector with std::pair<unsigned long, unsigned long> objects. I am trying to generate permutations of the objects of the vector using std::next_permutation() . However, I want the permutations to be of a given size, you know, similar to the permutations function in python where the size of the expected returned permutation is specified. Basically, the c++ equivalent of import itertools list = [1,2,3,4,5,6,7] for permutation in itertools.permutations(list, 3): print(permutation)

问题 How do I efficiently count the zero padded six digit numbers where the first three digits equal the last three? My solution is like this. But this is not efficient solution. I have to find best way public class TicketNumber { public static void main(String[] args) { int i1, i2, i3, i4, i5, i6, count = 0; String str=""; for (i1 = 0; i1 <= 9; i1++) { for (i2 = 0; i2 <= 9; i2++) { for (i3 = 0; i3 <= 9; i3++) { for (i4 = 0; i4 <= 9; i4++) { for (i5 = 0; i5 <= 9; i5++) { for (i6 = 0; i6 <= 9; i6++

问题 How do I efficiently count the zero padded six digit numbers where the first three digits equal the last three? My solution is like this. But this is not efficient solution. I have to find best way public class TicketNumber { public static void main(String[] args) { int i1, i2, i3, i4, i5, i6, count = 0; String str=""; for (i1 = 0; i1 <= 9; i1++) { for (i2 = 0; i2 <= 9; i2++) { for (i3 = 0; i3 <= 9; i3++) { for (i4 = 0; i4 <= 9; i4++) { for (i5 = 0; i5 <= 9; i5++) { for (i6 = 0; i6 <= 9; i6++

问题 This is what I got: <?php // Program to print all // combination of size r // in an array of size n function printCombinations($arr, $n, $r) { $data = []; combinationUtil($arr, $data, 0, $n - 1, 0, $r); } function combinationUtil($arr, $data, $start, $end, $index, $r) { if ($index == $r) { for ($j = 0; $j < $r; $j++) { echo $data[$j]; } echo "<br>"; return; } for ($i = $start; $i <= $end && $end - $i + 1 >= $r - $index; $i++) { $data[$index] = $arr[$i]; combinationUtil($arr, $data, $i + 1,

问题 Although there are numerous articles about generating permutations, I have an algorithmic need for permutation that's just a bit different. Given a set of elements (a, b, c, .. n) I construct pairs: (ab), (cd), (ef), ... in any combination of elements. Pairs (ab) and (ba) are identical. Also the needed permutations should not be different only in sequence: (ab), (ef), (cd) is identical to (ef), (cd), (ab) As an example, I'll show the exhaustive list of permutations for 6 elements a, b, c, d,

问题 Although there are numerous articles about generating permutations, I have an algorithmic need for permutation that's just a bit different. Given a set of elements (a, b, c, .. n) I construct pairs: (ab), (cd), (ef), ... in any combination of elements. Pairs (ab) and (ba) are identical. Also the needed permutations should not be different only in sequence: (ab), (ef), (cd) is identical to (ef), (cd), (ab) As an example, I'll show the exhaustive list of permutations for 6 elements a, b, c, d,