# 55. Jump Game 跳跃游戏

@TOC

## # 题目描述

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.
``````

## # 解题方法

### # 贪心

Python代码如下：

``````class Solution(object):
def canJump(self, nums):
"""
:type nums: List[int]
:rtype: bool
"""
reach = 0
for i, num in enumerate(nums):
if i > reach:
return False
reach = max(reach, i + num)
return True
``````

C++代码如下：

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

## # 日期

2018 年 10 月 28 日 —— 10月份最后一个周一 2019 年 1 月 11 日 —— 小光棍节？