最最简单的二分搜索

#include<bits/stdc++.h>
using namespace std;
#define max 1000
typedef pair<int,int>p;
#define INF  1e9+7
#define ll long long
#define eps 1e-6
int main(int argc, char const *argv[])
{
int a[5]={1,2,5,6,8};
int k=6;
int lb=-1,ub=5,mid;
while(ub-lb>1){
mid=(ub-lb)/2;
if (a[mid]>=k)
{
ub=mid;
}
else{
lb=mid;
}
}
printf("%d\n",ub );
return 0;
}