Jump Game Array

• Time : $O(n)$
• Space : $O(1)$

int Solution::canJump(vector<int> &A) {
    int p = 0, ma = 0, n = A.size();
    while(p <= ma and p < n) {
        ma = max(ma, A[p] + p);
        if(ma > p) p++;
        else break;
    }
    return p >= n - 1;
}