A 積雪深差:

# include <bits/stdc++.h>
using namespace std;
int main() {
    long long a, b;
    scanf("%lld%lld", &a, &b);
    printf("%lld", a - b);
    return 0;
}

B hacker:

# include <bits/stdc++.h>
using namespace std;
int T;
long long n, m;
int main() {
	scanf("%d", &T);
	while (T--) {
		scanf("%lld%lld", &n, &m);
		if (n == m) {
			printf("0\n");
			continue;
		}
		if ((n | m) == n || (n | m) == m) {
			printf("1\n");
		} else {
			printf("2\n");
		}
	}
	return 0;
}

C 存在:

# include <bits/stdc++.h>
using namespace std;
int n, a = 2, b = 0;
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++) {
		if (b == 0) {
			cout << a << " ";
			a++;
			b = 2;
		} else {
			b--;
			cout << 1 << " ";
		}
	}
	return 0;
}

D queue:

# include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 1e6 + 10;
struct node {
	string s; int id;
	bool operator < (const node &rhs) const {
		return id < rhs.id;
	}
}; set<node> q;
map<string, int> inq;
map<string, bool> ing;
inline bool try_insert(string s) {
	if (inq[s] || ing[s]) {
        return 0;
    }
	int x = q.empty() ? 0 : prev(q.end())->id;
	return q.insert({ s, inq[s] = x + 1 }), 1;
}
inline bool try_erase(string s) {
	if (!inq[s]) {
        return 0;
    }
	return q.erase({ s, inq[s] }), inq[s] = 0, 1;
}
string t[2]; int num;
inline void try_start() {
	for (int i = 0; i < num; i++) {
        ing[t[i]] = 0, try_insert(t[i]);
    }
	num = min<int>(2, q.size());
	if (!num) {
        return puts("Error"), void();
    }
	for (int i = 0; i < num; i++) {
		try_erase(t[i] = q.begin()->s), ing[t[i]] = 1;
		cout << t[i] << " ";
	}
	puts("");
}
int n;
string opt, s;
int main() {
	scanf("%d", &n);
	while (n--) {
		cin >> opt;
		if (opt[0] == 'a') {
			cin >> s;
			puts(try_insert(s) ? "OK" : "Error");
		}
		if (opt[0] == 'l') {
			cin >> s;
			puts(try_erase(s) ? "OK" : "Error");
		}
		if (opt[0] == 's') {
			try_start();
		}
	}
}