55.Jump Game

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.

思路：利用贪心策略，初始化设置step=nums[0],到下一步step--,并且取step=max(step,nums[i]),这样step一直保持是最大移动步数，如果step<=0,表示不能到达i位置，那么返回false。整个循环下来都没有返回说明能够顺利到达末尾的位置，返回true。

class Solution {
public:
    bool canJump(vector<int>& nums) {
        if(nums.size()<=1)
            return true;
        int step =nums[0];
        for(int i=1;i<nums.size();i++){
            if(step>0){
                step--;
                step=max(step,nums[i]);
            }
            else
                return false;
            
        }
        return true;
    }
};