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.

Example:

Input: [2,3,1,1,4]
Output: 2
Explanation: 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.
Note:

You can assume that you can always reach the last index.

 

public int jump(int[] nums) {
        /**
         * 此处基于贪婪的算法的前提是不管怎么跳都能到达终点，恰巧题目给出这个前提
         * 首先在到达位置0和位置0之前，必须跳跃一次，在到达0的过程中，能到的最远的位置是x;
         * 然后在从1开始到达位置x和位置x之前，必须跳跃一次，此次跳跃能达到的最远位置是...
         * 以此类推
         */
        int jumps = 0, end = 0, farthestDestination = 0;
        for(int i = 0; i < nums.length - 1; ++i) {
            farthestDestination = Math.max(farthestDestination, i + nums[i]);
            if(i == end) {
                ++jumps;
                end = farthestDestination;
            }
        }
        return jumps;
    }