C++ 代码

#include <iostream>

using namespace std;
const int N = 1e6 +10;
int x[N];

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

        int begin = r;

        l = 0, r = n -1;
        while(l < r)
        {
            int mid = r + l +1 >> 1;
            if(x[mid] <= m) l = mid;
            else r = mid -1;
        }
        int end = r;
        if(x[r] != m) cout << "-1 -1" << endl;
        else
        cout << begin << " " << end << endl;
    }
    return 0;
}