Array - 55. Jump Game - 码农教程

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.

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.

视频讲解： https://www.bilibili.com/video/BV1154y1D7m2

思路：

题目是说给定一个数组，每一位数字代表可以往前走几步，能走到最后一位就返回true。可以记录下每一步之后可以走的最大距离，然后更新这个最大距离，一次遍历就可以。

代码：

java:

class Solution {
    public boolean canJump(int[] nums) {
        if(nums == null || nums.length <= 1) return true;
        
        int max = 0;
        for (int i = 0; i < nums.length && i <= max; i++) {
            max = Math.max(nums[i] + i, max);
            if (max >= nums.length-1) return true;
        }
        
        return false;
    }
}

go：

func canJump(nums []int) bool {
    if nums == nil || len(nums) <= 1 {return true}
    
    reach := 0
    for i := 0; i < len(nums) && i <= reach; i++ {
        reach = func (x, y int) int {
            if x > y { return x }
            return y
        }(nums[i] + i, reach)
        if reach >= len(nums) -1 {return true}
    }
    
    return false
}