JumpGame.kt - master - uizadcz/Algorithm

/**
 * https://leetcode.com/problems/jump-game/?envType=study-plan-v2&envId=top-interview-150
 *
 * 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
 */

class Solution {

    fun canJump(nums: IntArray): Boolean {
        var maxReach = 0

        for (i in nums.indices) {
            if (i > maxReach) return false
            maxReach = Math.max(maxReach, i + nums[i])
        }

        return true
    }

    // fun canJump(nums: IntArray): Boolean {
    //     if (nums.size == 1) {
    //         return nums[0] == 0 ////
    //     }
    //
    //     var tmp = 0
    //     while (tmp < nums.size) {
    //         val inc = nums[tmp]
    //         if (inc == 0) {
    //             return false
    //         }
    //         tmp += inc
    //     }
    //
    //     return tmp >= nums.size
    // }

}