remove-element

packagecom.ytx.array;

/** 题目：remove-element

 *

 *     描述： Given an array and a value, remove all instances of that value in place and return the new length.

                    The order of elements can be changed. It doesn't matter what you leave beyond the new length.

 *

 *@authoryuantian xin

 * 

 *  给定一个数组和一个值，删除该值的所有实例，并返回新的长度。元素的顺序可以被改变，也不关心最终的数组长度。

 * 

 *  双指针思想，一个快指针i,一个慢指针index

 */

publicclass Remove_element {

       

       public int removeElement(int[]A,int elem) {

             

             /*int len = A.length;

              if(len == 0) return 0;

             int index = 0;

              for(int i = 0; i <len; i++) {

                     if(A[i] !=elem) {

                            A[index++] = A[i];

                     }

              }

            return index; */

             int len = A.length;

             for(inti=0;i<len;){

                  if(elem==A[i]){

                      A[i]=A[--len];//若相同则把最后一个位置元素覆盖过来，且重新检查覆盖过来的元素

                   }else{

                       ++i;

                   }

               }

              return len;

        }

       

       publicstatic void main(String[]args) {

             

             int[]A={1,2,2,4,5,2,6,2,2,2,7};

             intelem = 2;

             intnewlength = newRemove_element().removeElement(A,elem);

             for(inti = 0; i < newlength;i++) {

                    System.out.print(A[i] + " ");

             }

       }

}