Jump Game I

ID: 55

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.

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.

Idea

Greedy + traversal

Start from the beginning, calculate the max index that can be reached from that index. If final index >= nums.length-1, means that can step out, which means can reach end

For calculating, update max to Math.max(i+nums[i], max)

Code

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