Greedy Algorithm - Jump Game

You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length at that position.

Return true if you can reach the last index, or false otherwise.

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.

Solution:

var canJump = function(nums) {
    let maxReach = 0;  // This variable keeps track of the maximum index we can reach.

    for (let i = 0; i < nums.length; i++) {
        // If the current index is beyond the furthest reachable index, return false.
        if (i > maxReach) {
            return false;
        }

        // Update the furthest reachable index.
        maxReach = Math.max(maxReach, i + nums[i]);

        // If the furthest reachable index is at or beyond the last index, return true.
        if (maxReach >= nums.length - 1) {
            return true;
        }
    }

    return false;
};

Time Complexity: O(n)

Space Complexity: O(1)

Thank you for reading!