[題解]二分搜尋

a152. 二分搜尋

#include <bits/stdc++.h>
#define ll long long
#define ld  long double
#define N 1005
#define FOR(i,n) for(int i=0;i<n;i++)
#define pii pair<int,int>
using namespace std;

int main(){
    int n,arr[N];cin>>n;
    for(int i=0;i<n;i++)cin>>arr[i];
    int t;cin>>t;
    
    int pos = 0,ans = 0,find = 0,l = 0,r = n-1;    //[l,r]
    
    while(l<=r){
        int mid = (l+r)/2;
        ans++;
        if(arr[mid]==t){
            pos = mid;find = 1;break;
        }
        else if(arr[mid]>t)r = mid-1;
        else l = mid+1;
    }
    if(find)cout<<pos<<" "<<ans<<endl;
    else cout<<"not found "<<ans<<endl;
}