55-Jump-Game.cpp

/*
    Given int array, return true if can reach last index
    Ex. nums = [2,3,1,1,4] -> true, index 0 to 1 to last

    Greedy: At each point, determine furthest reachable index

    Time: O(n)
    Space: O(1)
*/

class Solution {
public:
    bool canJump(vector<int>& nums) {
        int n = nums.size();
        int reachable = 0;
        
        for (int i = 0; i < n; i++) {
            if (i > reachable) {
                return false;
            }
            reachable = max(reachable, i + nums[i]);
            if (reachable >= n - 1) {
                break;
            }
        }
        
        return true;
    }
};