Jump Game

Problem

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.

Constraints:

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

Solution

/**
 * @param {number[]} nums
 * @return {boolean}
 */
var canJump = function(nums) {
    let maxReach = nums[0];
    for (let i = 1; i < nums.length; i++) {
        if (maxReach >= i) {
            maxReach = Math.max(maxReach, nums[i] + i);
        }
    }
    return maxReach >= nums.length - 1;
};

We iterate through nums and keep track of the maximum possible index we can reach. If the maximum reach is greater than the last index of nums, there must be a way to reach the last index.

Problem​

Solution​

Problem

Solution