/**
  1. find exact value
 */
 
function search(nums: number[], target: number): number {
  let left = 0;
  let right = nums.length - 1;
 
  while (left < right) {
    let mid = Math.floor((left + right) / 2);
 
    if (nums[mid] === target) {
      return mid;
    }
 
    if (nums[mid] > target) {
      right = mid - 1;
    } else {
      left = mid + 1;
    }
  }
 
  return -1;
}
 
/**
  2. find upper bound
 */
 
function search(nums: number[], target: number): number {
  let left = 0,
    right = nums.length - 1;
 
  while (left < right) {
    const mid = Math.floor((left + right) / 2);
 
    if (nums[mid] >= target) {
      right = mid;
    } else {
      left = mid + 1;
    }
  }
 
  if (nums[left] !== target) {
    return -1;
  }
 
  return left;
}
 
/**
  3. find lower bound -- not working for binary search
 */
 
function search(nums: number[], target: number): number {
  let left = 0,
    right = nums.length - 1;
 
  while (left < right) {
    const mid = Math.floor((left + right) / 2);
 
    if (nums[mid] < target) {
      left = mid;
    } else {
      right = mid - 1;
    }
  }
 
  console.log(left);
 
  if (nums[left] !== target) {
    return -1;
  }
 
  return left;
}