Extract (and remove) duplicates...
Author
Given a sorted container, is there any algorithms combo in STL to extract duplicates out into another empty container? Or better still, I''m thinking something like this:
container1 elements: [1 2 2 3 3 4]
after the process:
container1 elements: [1 4]
new container2 elements: [2 3]
std::unique_copy and the erase member function on your container will get you from:c1: [1 2 2 3 3 4]
to:
c2: [1 2 3 4]
std::set_difference will get you even further:c1: [1 2 2 3 3 4]
c2: [1 2 3 4]
c3: [2 3]
c4: [1 4]
Update GameDev.net system time campaign - success at last
[edited by - dalleboy on March 8, 2003 11:28:24 AM]
#include <vector>#include <algorithm>#include <iterator>#include <iostream>void print(const char* name, const std::vector<int>& vec){ std::vector<int>::const_iterator pIter = vec.begin(); const std::vector<int>::const_iterator pIterEnd = vec.end(); std::cout << name << ": "; for (; pIter != pIterEnd; ++pIter) { std::cout << *pIter << " "; } std::cout << std::endl;}int main(){ const int pStart[] = { 1, 2, 2, 3, 3, 4 }; std::vector<int> vecAll(pStart, pStart + 6); print("vecAll", vecAll); std::sort(vecAll.begin(), vecAll.end()); print("vecAll", vecAll); std::vector<int> vecAllUniques; vecAllUniques.reserve(vecAll.size()); std::unique_copy(vecAll.begin(), vecAll.end(), std::back_inserter(vecAllUniques)); print("vecAllUniques", vecAllUniques); std::vector<int> vecOnlyDuplicates; vecOnlyDuplicates.reserve(vecAll.size()); std::set_difference(vecAll.begin(), vecAll.end(), vecAllUniques.begin(), vecAllUniques.end(), std::back_inserter(vecOnlyDuplicates)); print("vecOnlyDuplicates", vecOnlyDuplicates); std::vector<int> vecOnlyUniques; vecOnlyUniques.reserve(vecAllUniques.size()); std::set_difference(vecAllUniques.begin(), vecAllUniques.end(), vecOnlyDuplicates.begin(), vecOnlyDuplicates.end(), std::back_inserter(vecOnlyUniques)); print("vecOnlyUniques", vecOnlyUniques);} [edited by - dalleboy on March 8, 2003 11:30:11 AM]
You also may have to make the vecOnlyDuplicates result vector unique, it will contain duplicates itself if the original vector have more than 2 duplicates in a row:
vecAll: 1 2 2 3 3 3 4
vecAllUniques: 1 2 3 4
vecOnlyDuplicates: 2 3 3
vecOnlyUniques: 1 4
To fix this, do like this:
Update GameDev.net system time campaign - success at last
vecAll: 1 2 2 3 3 3 4
vecAllUniques: 1 2 3 4
vecOnlyDuplicates: 2 3 3
vecOnlyUniques: 1 4
To fix this, do like this:
vecOnlyDuplicates.erase(std::unique(vecOnlyDuplicates.begin(), vecOnlyDuplicates.end()), vecOnlyDuplicates.end()); Update GameDev.net system time campaign - success at last
Author
Yeah, that kinda solve what I really want. Anyway thanks alot. 
Is there any other way with lesser step, of course, that is possible for STL?
...Getting c2 from c1, all that I could think of is using custom loop.
Is there any other way with lesser step, of course, that is possible for STL? //-----------// your steps:c1: [1 2 2 3 3 4]c2: [1 2 3 4]c3: [2 3]c4: [1 4] //-----------// i hope:c1: [1 2 2 3 3 4]c2: [2 3]c3: [1 4] ...Getting c2 from c1, all that I could think of is using custom loop.
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