Container With Most Water

• Time : $O(n)$
• Space : $O(1)$

int Solution::maxArea(vector<int> &A) {
    int l = 0, r = A.size() - 1;
    int res = 0;
    while(l < r) {
        res = max(res, (r - l) * min(A[l], A[r]));
        if(A[l] < A[r]) l++;
        else r--;
    }
    return res;
}