Conduct Dot Product of two large Vectors

 package fb;

 public class DotProduct {

     public int dotPro(int[][] v1, int[][] v2) {

         int[][] shortV;

         int[][] longV;

         if (v1.length < v2.length) {

             shortV = v1;

             longV = v2;

         }

         else {

             shortV = v2;

             longV = v1;

         }

         int res = 0;

         for (int i=0; i<shortV.length; i++) {

             int shortIndex = shortV[i][0];

             int shortValue = shortV[i][1];

             int longSeq = binarySearch(longV, shortIndex);

             if (longSeq >= 0) {

                 res += shortValue * longV[longSeq][1];

             }

         }

         return res;

     }

     public int binarySearch(int[][] arr, int target) {

         int l=0, r=arr.length-1;

         while (l <= r) {

             int m = (l+r)/2;

             if (arr[m][0] == target) return m;

             else if (arr[m][0] < target) l = m + 1;

             else r = m - 1;

         }

         return -1;

     }

     /**

      * @param args

      */

     public static void main(String[] args) {

         // TODO Auto-generated method stub

         DotProduct sol = new DotProduct();

         int[][] v2 = new int[][]{{0,2},{1,3},{5,2},{7,1},{10,1}};

         int[][] v1 = new int[][]{{1,6},{7,2}};

         int res = sol.dotPro(v1, v2);

         System.out.println(res);

     }

 }