算法描述：

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.

Example 1:

Input: [2,3,1,1,4]
Output: true
Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index.

Example 2:

Input: [3,2,1,0,4]
Output: false
Explanation: You will always arrive at index 3 no matter what. Its maximum
             jump length is 0, which makes it impossible to reach the last index.

解题思路：贪心法，求出当前位置所能到达的最大位置。如果该位置大于最大到达位置，则返回false.

    bool canJump(vector<int>& nums) {
        int reach = 0;
        for(int i=0; i < nums.size(); i++){
            if(i > reach) return false;
            reach = max(i+nums[i],reach);
        }
        return true;
    }