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  1. Prepare
  2. Algorithms
  3. Sorting
  4. Quicksort 1 - Partition
  5. Discussions

Quicksort 1 - Partition

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401 Discussions

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  • ahmet_alp77
     + 0 comments

    Java:

    public static List<Integer> quickSort(List<Integer> arr) {
    int pivot = arr.get(0);
    List<Integer> lArr = new ArrayList<>();
    List<Integer> rArr = new ArrayList<>();
    rArr.add(pivot);
    for (int j=1; j < arr.size(); j++) {
        if (arr.get(j) < pivot) {
            lArr.add(arr.get(j));
        } else {
            rArr.add(arr.get(j));
        }
    }
    lArr.addAll(rArr);
    return lArr;
}

  • yashdeora98294
     + 0 comments

    Here is problem solution in python java c++ c and javascript - https://programmingoneonone.com/hackerrank-quicksort-1-partition-problem-solution.html

  • kundan5184
     + 0 comments

    vector quickSort(vector arr) { int i=0; int j=arr.size()-1; int p = arr[0]; while(i=arr[i])i++; while(p<=arr[j])j--; if(i

  • alban_tyrex
     + 0 comments

    Here is my c++ solution, you can watch the explanation here : https://youtu.be/2HD41pYh8cU

    vector<int> quickSort(vector<int> arr) {
    vector<int> left, equal, right;
    for(int i = 0; i < arr.size(); i++){
        if(arr[i] < arr[0]) left.push_back(arr[i]);
        else if(arr[i] > arr[0]) right.push_back(arr[i]);
        else equal.push_back(arr[i]);
    }
    left.insert(left.end(), equal.begin(), equal.end());
    left.insert(left.end(), right.begin(), right.end());
    return left;
}

  • emhhacker
     + 0 comments

    My Java solution with o(n) time complexity and o(n) space complexity:

    public static List<Integer> quickSort(List<Integer> arr) {
        if(arr.size() == 1) return arr; //already sorted
        
        int pivot = arr.get(0); // pivot is always arr[0]
        //declare each subarray
        List<Integer> left = new ArrayList<>();
        List<Integer> right = new ArrayList<>();
        List<Integer> equal = new ArrayList<>();
        
        //partition the og arr
        for(int element : arr){
            if(element < pivot) left.add(element);
            else if (element > pivot) right.add(element);
            else equal.add(element);
        }
        
        //combine the subarrays
        List<Integer> combinedList = 
            Stream.of(left, equal, right)
            .flatMap(List::stream)
            .collect(Collectors.toList());
        return combinedList;
    }