#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
vector<int> a{1, 2, 3, 4, 5, 5, 6, 7, 8};
auto it1 = lower_bound(a.begin(), a.end(), 5);
cout << "*it1:" << *it1 << ", distance:" << distance(a.begin(), it1) << endl; // 5, 4, 这里找到的是第一个5
auto it2 = upper_bound(a.begin(), a.end(), 5);
cout << "*it2:" << *it2 << ", distance:" << distance(a.begin(), it2) << endl; // 6, 6
return 0;
}