A8022.查找

IO不加速+手搓二分

#include <iostream>
using namespace std;

const int maxn = 1e6;//n的最大值 
int n, m, a[maxn+5];

int main() {
	//输入数据 
	cin >> n >> m;
	for (int i=1; i<=n; i++)
		cin >> a[i];
	while (m--) {
		int q;
		cin >> q;
		//二分查找 
		int l=1, r=n, ans=-1;
		while (l < r) {
			int mid = l+r>>1;
			if (a[mid] >= q) {
				ans = mid;
				r = mid; 
			}else {
				l = mid+1; 
			}
		} 
		if (a[ans] == q)
			cout << ans << ' ';
		else
			cout << "-1 ";
	}
  return 0;
}
}