Median of Array

• Time : $O(logn)$
• Space : $O(1)$

double Solution::findMedianSortedArrays(const vector<int> &A, const vector<int> &B) {
    int n = A.size(), m = B.size();
    if(n > m) return findMedianSortedArrays(B,A);
    int l = 0, r = n, med = (n + m) / 2;
    while(l <= r) {
        int i = l + (r - l) / 2;
        int j = med - i;
        if(i > 0 and A[i-1] > B[j]) r = i - 1;
        else if(i < n and A[i] < B[j-1]) l = i + 1;
        else {
            int r = (i == n) ? B[j] : (j == m) ? A[i] : min(A[i],B[j]);
            if((n + m) & 1) return r;
            int l = (i == 0) ? B[j-1] : (j==0) ? A[j-1] : max(A[i-1],B[j-1]);
            return (l + r) / 2.;
        }
    }
    return -1;
}