Leetcode题解55- Jump Game

题目：

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.

思路：贪心法，从前往后依次搜索最远达到距离。

代码

class Solution {
public:
    //贪心法，从前往后搜索最远达到距离
    bool canJump(vector<int>& nums) {
        if(nums.size()==0) return false;
        int reach=nums[0], i=0;
        while(i <= reach && i < nums.size()-1){       
            reach = max(reach, i+nums[i]);    //选择最远达到距离
            i++;
        }
        if(reach >= nums.size()-1) return true;
        return false;        
    }
};