Jump Game II Java

Given an array of non-negative integers, you are initially positioned at the first index of the array.

Each element in the array represents your maximum jump length at that position.

Your goal is to reach the last index in the minimum number of jumps.

For example:
Given array A = [2,3,1,1,4]

The minimum number of jumps to reach the last index is 2. (Jump 1 step from index 0 to 1, then 3 steps to the last index.)

Extension ofJump Game

     Optimize the number of step as well

     now we have step & step -1

     when step-1 can not reach current position i, then

     we need step++, then make current position reachable.

public class Solution {    public int jump(int[] A) {        int len=A.length;        if(len==0) return 0;        int reach=0;        int step=0;        int lastReach=0;        for(int i=0;i<=reach && i<len;i++) {            //can not reach current position            if (i > lastReach) {                step++;                lastReach = reach;            }            reach = Math.max(reach, A[i] + i);        }        return reach>=len-1?step:0;    }}