BinarySearch.java

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 */

// Binary Search

class Solution {
  public int binarySearch(int[] nums, int target) {
    if (nums == null || nums.length == 0) { return -1; }

    int start = 0, end = nums.length - 1;
    while (start + 1 < end) {
      int mid = start + (end - start) / 2;
      if (nums[mid] == target) {
        return mid;
      } else if (nums[mid] < target) {
        start = mid;
      } else {
        end = mid;
      }
    }

    if (nums[start] == target) {
      return start;
    }
    if (nums[end] == target) {
      return end;
    }
    
    return -1;
  }
}