希尔排序算法思想

//希尔排序
input: an array a of length n with array elements numbered 0 to n − 1
gap ← round(n/2)
while gap > 0 do:    
    for i = gap to n − 1 do:        
        temp ← a[i]        
        j ← i        
        while j ≥ gap and a[j − gap] > temp do:            
            a[j] ← a[j − gap]            
            j ← j − gap       
        a[j] ← temp    
    gap ← round(gap / 2)

@Test
    public void test(){
        Integer[]  arr= {8, 5, 10, 12, 7, 6, 15, 9, 11, 3};
        for (int group = arr.length / 2; group > 0; group /= 2) {
            for (int i = group; i < arr.length; i++) {
                for (int j = i - group; j >= 0; j -= group) {
                    if (arr[j] > arr[j + group]) {
                        int temp = arr[j];
                        arr[j] = arr[j + group];
                        arr[j + group] = temp;
                    }
                }
            }
        }
        for(Integer it : arr){
            System.out.print("  "+it);
        }
    }

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