55. Jump Game（重要）

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​​.​​[3,2,1,0,4]​​, return ​​false​​.

贪心算法。记录目前为止能到达的最远位置。

class Solution {
public:
  bool canJump(vector<int>& nums) {
    int len=nums.size();
    if(len==0) return true;
    
    int reach=0;
    for(int i=0;i<len;i++){
        if(reach<i){
        return false;//有可能中间就无法到达
      }
      reach=max(nums[i]+i,reach);
    }
    if(reach<len-1)
      return false;
    return true;
  }
};