lower_bound( )和upper_bound( )

#include<bits/stdc++.h>

using namespace std;

const int maxn=100000+10;

const int INF=2*int(1e9)+10;

#define LL long long

int cmd(int a,int b){

    return a>b;

}

int main(){

    int num[6]={1,2,4,7,15,34}; 

    sort(num,num+6);                           //按从小到大排序 

    int pos1=lower_bound(num,num+6,7)-num;    //返回数组中第一个大于或等于被查数的值 

    int pos2=upper_bound(num,num+6,7)-num;    //返回数组中第一个大于被查数的值

    cout<<pos1<<" "<<num[pos1]<<endl;

    cout<<pos2<<" "<<num[pos2]<<endl;

    sort(num,num+6,cmd);                      //按从大到小排序

    int pos3=lower_bound(num,num+6,7,greater<int>())-num;  //返回数组中第一个小于或等于被查数的值 

    int pos4=upper_bound(num,num+6,7,greater<int>())-num;  //返回数组中第一个小于被查数的值 

    cout<<pos3<<" "<<num[pos3]<<endl;

    cout<<pos4<<" "<<num[pos4]<<endl;

    return 0;    

}