A 时间旅人的困境 - C++ 基本结构

while (c != 1) {
    if (c & 1) c = c * 3 + 1;
    else c >>= 1;
    ++ans;
} cout << ans << '\n';

B 完美风暴 - 数组

cin >> n;
for (int i = 1; i <= n; ++i) cin >> p[i];
for (int i = 1; i <= 7; ++i) cin >> a[i];
for (int i = 1; i <= n; ++i) ans += a[p[i]];
cout << ans << '\n';

C 加密的日记 - 字符与字符串

cin >> n;
cin.ignore(numeric_limits<streamsize>::max(), '\n');
getline(cin, s);
for (auto &v : s) if (v != ' ') {
    char base = isupper(v) ? 'A' : 'a';
    v = (v - base + 26 - n) % 26 + base;
} cout << s << '\n';

D 图书馆管理系统 - 结构体与 STL

int n, x;
string op, name, author;
struct book {
    string name, author;
    bool borrowed;
};
map<int, book> mp;

cin >> n;
while (n--) {
    x = 0;
    cin >> op;
    if (op == "ADD") {
        cin >> name >> author >> x;
        if (name.empty() || author.empty() || !x) {
            cout << "Invalid\n";
            break;
        } mp[x].name = name, mp[x].author = author;
    } else if (op == "QUERY") {
        cin >> x;
        if (!mp.count(x)) cout << "NotFound\n";
        else {
            if (mp[x].borrowed) cout << mp[x].name << ' ' << mp[x].author << ' ' << x << " Borrowed\n";
            else cout << mp[x].name << ' ' << mp[x].author << ' ' << x << " Available\n";
        }
    } else if (op == "BORROW") {
        cin >> x;
        if (!mp.count(x)) cout << "NotFound\n";
        else mp[x].borrowed = true;
    } else {
        cin >> x;
        if (!mp.count(x)) cout << "NotFound\n";
        else mp[x].borrowed = false;
    }
}

E 方案 - 图的存储与遍历

const int N = 1010;
int t, n, m, r, u, v;
vector<pair<int, long long> > g[N];
long long k, w, dis[N], ans[N], sum;

void dfs(int u, int fa){
    for (auto to : g[u]) {
        int v = to.first;
        long long w = to.second;
        if(v == fa) continue;
        dis[v] = dis[u] + w;
        dfs(v, u);
    }
}

cin >> t >> k;
for (int i = 1; i <= t; ++i){
    for (int j = 1; j <= n; ++j) g[j].clear();
    fill(dis + 1, dis + n + 1, 0);
    cin >> n >> m >> r;
    for (int i = 1; i <= m; ++i) {
        cin >> u >> v >> w;
        g[u].emplace_back(make_pair(v, w));
        g[v].emplace_back(make_pair(u, w));
    } dfs(r, 0);
    for (int j = 1; j <= n; ++j) ans[i] = max(ans[i], dis[j]);
} for (int i = 1; i <= t; ++i) sum += ans[i];
if (sum >= k) cout << "YES\n" << sum << '\n';
else {
    cout << "NO\n";
    for (int i = 1; i <= t; ++i) cout << ans[i] << ' ';
}

F 血夜筝鸣 - 动态规划基础

cin >> n;
for (int i = 1; i <= n; ++i)
    for (int j = 0; j < 3; ++j) cin >> a[i][j];
for (int i = 1; i <= n; ++i) {
    f[i][0] = max(f[i - 1][0], max(f[i - 1][1], f[i - 1][2])) + a[i][0];
    f[i][1] = max(f[i - 1][0], max(f[i - 1][1], f[i - 1][2])) + a[i][1];
    f[i][2] = max(f[i - 1][0], f[i - 1][1]) + a[i][2];
} cout << max(f[n][0], max(f[n][1], f[n][2])) << '\n';