LintCode "The Smallest Difference"

Binary search.

class Solution {
    int _findClosest(vector<int> &A, int v)
    {
        int s = , e = A.size() - ;
        int ret = INT_MAX;
        while(s <= e)
        {
            int mid = (s + e) / ;
            int vmid = A[mid];
            int dist = abs(vmid - v);
            ret = min(ret, dist);

            if(vmid == v) return ;
            if(vmid < v)
            {
                s = mid + ;
            }
            else if(vmid > v)
            {
                e = mid - ;
            }
        }
        return ret;
    }
public:
    /**
     * @param A, B: Two integer arrays.
     * @return: Their smallest difference.
     */
    int smallestDifference(vector<int> &A, vector<int> &B) {
        sort(A.begin(), A.end());

        int ret = INT_MAX;
        for(auto vb : B)
        {
            ret = min(ret, _findClosest(A, vb));
        }
        return ret;
    }
};