[JAVA] Binary search binary search method

Binary search binary search method

Search method to search while narrowing the range in half

merit

Search speed is fast

Demerit

Data needs to be sorted in advance

BinarySerch.java

class BinarySerch{
  public static void main(String[] args){
   //Sorted array to search
   int a[] = {1,3,6,8,10};
   //Value to search
   int serchValue = 3;
   //The sequence number of the found data The initial value is an error value (-1）
   int find = -1;

   //Leftmost and rightmost numbers to search
   int left = 0;
   int right = a.length-1;
   //Repeat when there is data on the left and right edges to check
   while(left <= right){
     //Specify the position to check the number in the middle of the left and right
     int middle = (int)((left + right)/2);
     //Compare the value of the position to look for with the position to look for
     if(a[middle] == serchValue){
        //If they are the same, save the number and end the iteration
        find = middle;
        break;
    }else if (a[middle] < serchValue){
    //If it is smaller than the value you are looking for, move the left edge
     left = middle + 1;
    }else {
    //If it is larger than the value you are looking for, move the right edge
    right = middle - 1;
    }
  }
  //Display search results
  System.out.println("search results:" + find);
 }
}

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