本地没法输入，提交之后tle

Frank123123123 @ 2024-08-28 14:24:05

#include<bits/stdc++.h>
using namespace std;

int main(){
    int m,n;
    cin>>m>>n;
    int a[1000010]={0};
    for(int i=1;i<=m;i++){
        cin>>a[i];
    }
    for(int i=1;i<=n;i++){
        int q;
        cin>>q;
        int l=1,r=m;
        while(l<r){
            int mid=(l+r)/2;
            if(a[mid]<q){
                l=mid+1;
            }
            else if(a[mid]>q){
                r=mid;
            }
            else{
                l=mid;
            }
        }
        if(a[l]==q){
            cout<<l;
        }
        else{
            cout<<-1;
        }
    }

    return 0;
}

by Frank123123123 @ 2024-08-28 14:26:13

我初学二分

by 违规用户名Jx9)zIu @ 2024-08-28 14:27:49

#include<bits/stdc++.h>
using namespace std;
long long a[1000005];
int main(){
    int n,m;
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=m;i++){
        int q;
        cin>>q;
        int l=1,r=n,mid;
        while(l<r){
            mid=(l+r)/2;
            if(a[mid]>=q){
                r=mid;
            }else{
                l=mid+1;
            }
        }
        if(a[l]==q){
            cout<<l<<" ";
        }else{
            cout<<-1<<" ";
        }
    }
    return 0;
}

by Y204335 @ 2024-08-28 14:28:00

@Frank123123123 变量开全局，别开局部，开局部爆空间了

by 违规用户名Jx9)zIu @ 2024-08-28 14:28:26

@Frank123123123

求关

by ZengZeng_xy @ 2024-08-28 15:05:01

变量开全局，这样变量默认初值为零，不用初始化。

二分里面加上q==a[mid]的情况

by ZengZeng_xy @ 2024-08-28 15:08:36

like this

#include<bits/stdc++.h>
using namespace std;
int a[1000010];
int m,n;

int main(){
    ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=m;i++){
        int q;
        cin>>q;
        int l=1,r=n;
        while(l<r){
            int mid=l+r>>1;
            if(a[mid] == q){
                r=mid;
            }
            else if(a[mid]<q){
                l=mid+1;continue;
            }
            else if(a[mid]>q){
                r=mid-1;continue;
            }
            //cout<<l<<' '<<r<<'\n';
        }
        if(a[l]==q){
            cout<<l<<' ';
        }
        else{
            cout<<-1<<' ';
        }
    }

    return 0;
}

by ZengZeng_xy @ 2024-08-28 15:12:42

@Frank123123123 点个关注呗（喜

by Frank123123123 @ 2024-08-28 15:22:34

@ZengZeng_xy\ 已关