26--jump-game.java

class Solution {
    public boolean canJump(int[] nums) {
        int reachable = 0;
        for (int i = 0; i < nums.length && i <= reachable; i++) {
            reachable = Math.max(reachable, i + nums[i]);
            if (reachable >= nums.length - 1)
                return true;
        }
        return false;
    }
} // TC: O(n), SC: O(1)