leetcode/src/s0704_binary_search.cpp

#include "s0704_binary_search.hpp"

// 闭区间写法
int S0704::binSearch1(vector<int>& nums, int target) {
  int len = nums.size();
  int l{0};
  int r = len - 1;
  while (l <= r) {
    int m = (l + r) >> 1;
    if (target < nums[m]) {
      r = m - 1;
    } else if (nums[m] < target) {
      l = m + 1;
    } else {
      return m;
    }
  }
  return -1;
}

// 开区间写法
int S0704::binSearch2(vector<int>& nums, int target) {
  int len = nums.size();
  int l{0};
  int r = len;
  while (l < r) {
    int m = (l + r) >> 1;
    if (target < nums[m]) {
      r = m;
    } else if (nums[m] < target) {
      l = m + 1;
    } else {
      return m;
    }
  }
  return -1;
}