插入排序

public class InsertSort {

    /**
     * 直接插入：先确定一个有序列表，再不断取元素插入有序列表，扩大范围
     * @param arrays
     * @param length
     * @param isUp
     * @return
     */
    public static int[] insertDirect(int[] arrays,int length,boolean isUp){

        for(int i = 1;i < length;i++){
            int p = i;
            int tmp = arrays[i];
            if(isUp){//小到大
                while(p>0&&arrays[p-1]>tmp){
                    arrays[p] = arrays[p-1];
                    p--;
                }
                arrays[p] = tmp;
            }else{//大到小
                while(p>0&&arrays[p-1]<tmp){
                    arrays[p] = arrays[p-1];
                    p--;
                }
                arrays[p] = tmp;
            }

        }

        return arrays;
    }
    /**
     * 折半插入：在直接插入的基础上，在有序序列中折半缩小范围，减少比较次数
     * @param arrays
     * @param length
     * @param isUp
     * @return
     */
    public static int[] brinayInsert(int[] arrays,int length,boolean isUp){

        for(int i = 1;i < length;i++){

            int tmp = arrays[i];
            int start = 0;
            int end = i;
            while(start<end){
                int mid = start+(end-start)/2;
                if((tmp >= arrays[mid])&&(isUp==true)){
                    start = mid+1;
                }else if((tmp <= arrays[mid])&&(isUp==false)){
                    start = mid+1;
                }else{
                    end = mid;
                }
            }
            int p = i;
            while(p>end){
                arrays[p] = arrays[p-1];
                p--;
            }
            arrays[p] = tmp;
        }

        return arrays;
    }
    /**
     * shell排序，在直接插入的基础上升级
     * @param arrays
     * @param length
     * @param isUp
     * @return
     */
    public static int[] shellSort(int[] arrays,int length,boolean isUp){
        int len = length/2;
        while(len >= 1){
            for(int i = len;i<length;i += len){
                int p = i;
                int tmp = arrays[i];
                if(isUp){//小到大
                    while(p>0&&arrays[p-len]>tmp){
                        arrays[p] = arrays[p-len];
                        p -= len;
                    }
                    arrays[p] = tmp;
                }else{//大到小
                    while(p>0&&arrays[p-len]<tmp){
                        arrays[p] = arrays[p-len];
                        p -= len;
                    }
                    arrays[p] = tmp;
                }

            }
            len = len/2;
        }
        return arrays;
    }
}