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.
Determine if you are able to reach the last index.
For example:
A = [2,3,1,1,4], return true.
A = [3,2,1,0,4], return false.

这题的思想是局部最优解和全局最优解，见MaxSubarray那题的分析。
局部最优解nums[i]+i表示从当前的index可以跳到的最远距离。全局最优解maxCover代表总共能触及的最远距离。

    public boolean canJump(int[] nums) {
        int maxCover = 0;
        for (int i = 0; i <= nums.length - 1 && i <= maxCover; i++) {
            maxCover = Math.max(maxCover,nums[i]+i);
            if (maxCover>=nums.length-1) return true;
        }
        return false;
    }