README.md

55. Jump Game

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 (Ruby)

1. Greedy

# @param {Integer[]} nums
# @return {Boolean}
def can_jump(nums)
  max_index = 0

  (0...nums.size).each do |i|
    return false if i > max_index

    max_index = [max_index, i + nums[i]].max
  end

  true
end

Solutions (Rust)

1. Greedy

impl Solution {
    pub fn can_jump(nums: Vec<i32>) -> bool {
        let mut max_index = 0;

        for i in 0..nums.len() {
            if i > max_index as usize {
                return false;
            }
            max_index = max_index.max(i as i32 + nums[i]);
        }

        true
    }
}