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.)
思路：用Max表示[0, i⑴]能到达的最远距离，cur表示用ans步到达的距离。那末如果cur<i的话，代表它需要再走1步，所以它就能够到达前i⑴能到达的最远距离，可以这么想Max1定是某个位置起跳的，而cur也1定是大于等于Max的起始位置的，由于每一个位置的是都是非负数，所以cur1定是>=Max的起始位置的，可以动手写写。