LintCode: Cosine Similarity

C++

 class Solution {
 public:
     /**
      * @param A: An integer array.
      * @param B: An integer array.
      * @return: Cosine similarity.
      */
     double cosineSimilarity(vector<int> A, vector<int> B) {
         // write your code here
         int AB = , size;
         double lenA = , lenB = ;
         size = A.size();
         for (int i = ; i < size; i++) {
             AB += A[i]*B[i];
             lenA += A[i]*A[i];
             lenB += B[i]*B[i];
         }
         if ( == AB &&  == lenA &&  == lenB) {
             return ;
         } else {
             return AB/(sqrt(lenA)*sqrt(lenB));
         }

     }
 };