golang力扣leetcode 278.第一个错误的版本

package main
/**
 * Forward declaration of isBadVersion API.
 * @param   version   your guess about first bad version
 * @return          true if current version is bad
 *                false if current version is good
 * func isBadVersion(version int) bool;
 */
func firstBadVersion(n int) int {
  left, right := 1, n
  for left+1 < right {
    mid := left + (right-left)/2
    if !isBadVersion(mid) {
      left = mid
    } else {
      right = mid
    }
  }
  if isBadVersion(left) {
    return left
  }
  return right
}