Method partition

Lecture 42 Quick Sort/src/Main.java:12–31

(int[] arr, int st, int end)

        arr[y] = temp;
    }
    static int partition(int[] arr, int st, int end){
        int pivot = arr[st];
        int cnt = 0;
        for(int i = st+1; i <= end; i++){
            if(arr[i] <= pivot) cnt++;
        }
        int pivotIdx = st + cnt;
        swap(arr, st, pivotIdx);
        int i = st, j = end;
        while(i < pivotIdx && j > pivotIdx){
            while (arr[i] <= pivot) i++;
            while (arr[j] > pivot) j--;
            if(i < pivotIdx && j > pivotIdx){
                swap(arr, i, j);
                i++;
                j--;
            }
        }
        return pivotIdx;
    }
    static void quickSort(int[] arr, int st, int end){
        if(st >= end) return;
        int pi = partition(arr, st, end);