Insert sorting instance and JAVA Implementation

Insert sorting is a simple sorting method, which can be divided into direct insertion sorting and other insertion sorting methods derived from direct insertion sorting.

The basic idea of insert sorting is: in the number of groups to be sorted, suppose n-1 [n> = 2] Number is already sorted, now we need to insert the nth number into the preceding ordered number, so that the N number is in the correct order. This repeats until all the rows are sorted.

The algorithm complexity of this sort method is O (n). Its JAVA Implementation is as follows:

// Insert_sort

Publicint[] Insert_sort (Int[]
ARR ){

Int[] Intarr = arr;

IntI, j, key;

For(J = 1; j <intarr. length; j ++ ){

Key = intarr [J];

I = J-1;

While(I> = 0 & intarr [I]> key ){

Intarr [J] = intarr [I];

I --;

}

Intarr [I + 1] = key;

}

ReturnIntarr;

}

Instance:

Sort the sequence 1, 3, 2, and 5 by inserting a sort order. The sorting process is as follows:

(1) j = 1, key = 3, I = 0 ------- 1 3 2 5

(2) J = 2, key = 2, I = 1--------1 2 3 5

(3) J = 3, key =, I = 2--------1 2 3 5

In the above example, the I auto-subtraction step is omitted. The actual step is to compare intarr [J] with all the elements in front of it every time j increases by 1, when the element before intarr [J] is greater than that before intarr [J], it is exchanged with an element before it until the sorting is complete.