Codeforces Round #769 (Div. 2)

A

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int T, n;
int main() {
    cin >> T;
    while (T -- ) {
        cin >> n;
        string s;
        cin >> s;
        if (s.size() == 1 || s == "01" || s == "10")	cout << "YES" << endl;
        else cout << "NO" << endl;
    }
    return 0;
}

B
打表找规律

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int n, m;
int a[N];
int main() {
    int T;
    cin >> T;
    while (T -- ) {
        cin >> n;
        n --;
        int num = 1;
        int l;
        while (true) {
            if (num * 2 > n) {
                l = num;
                break;
            }
            num *= 2;
        }
        for (int i = n ; i >= l; i -- )
            cout << i << " ";
        for (int i = 0; i < l; i ++ )
            cout << i << " ";
        cout << endl;
    }
    return 0;
}

C
暴力

#include <bits/stdc++.h>
using namespace std;
int T, a, b;
int main() {
    cin >> T;
    while (T -- ) {
    	cin >> a >> b;
    	int res;
    	for (int i = b; ; i ++ ) {
    		if ((i | a) == i) {
    			res = i - b + 1;
    			break;
    		}
    	}
    	for (int i = a; ; i ++ ) {
    		if ((i | b) == b) {
    			res = min(res, i - a + 1);
    			break;
    		}
    	}
    	cout << min(res, b - a) << endl;
    }
    return 0;
}