Jump Game 2

Problem

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.)

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Idea

不太好理解，见代码。 大体思路是对于每一个能找到的最大区间，继续寻找在区间内能走到的最远距离.

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Solution

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