README_EN.md

55. Jump Game

中文文档

Description

Given an array of non-negative integers nums, 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: nums = [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: nums = [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.

 

Constraints:

• 1 <= nums.length <= 3 * 104
• 0 <= nums[i] <= 105

Solutions

Python3

class Solution:
    def canJump(self, nums: List[int]) -> bool:
        mx = 0
        for i, num in enumerate(nums):
            if i > mx:
                return False
            mx = max(mx, i + num)
        return True

Java

class Solution {
    public boolean canJump(int[] nums) {
        int mx = 0;
        for (int i = 0; i < nums.length; ++i) {
            if (i > mx) {
                return false;
            }
            mx = Math.max(mx, i + nums[i]);
        }
        return true;
    }
}

C++

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

Go

func canJump(nums []int) bool {
	mx := 0
	for i, num := range nums {
		if i > mx {
			return false
		}
		mx = max(mx, i+num)
	}
	return true
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

C#

public class Solution {
    public bool CanJump(int[] nums) {
        int mx = 0;
        for (int i = 0; i < nums.Length; ++i)
        {
            if (i > mx)
            {
                return false;
            }
            mx = Math.Max(mx, i + nums[i]);
        }
        return true;
    }
}

...