Submission #1054292

#	Time	Username	Problem	Language	Result	Execution time	Memory
1054292		manhlinh1501	Bitaro’s Party (JOI18_bitaro)	C++17	0 / 100	3 ms	11100 KiB

bitaro

#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
using i64 = long long;
const int MAXN = 2e5 + 5;
const int BLOCK_SIZE = 200;
#define ALL(a) (a).begin(), (a).end()
int N, M, Q;
vector<int> adj[MAXN];
bool is_deleted[MAXN];
vector<pii> dp[MAXN];
int dist[MAXN];
bool f[MAXN];

vector<pii> merge_vector(vector<pii> &x, vector<pii> &y) {
    vector<pii> z;
    int px = 0, py = 0;
    while((int)z.size() <= BLOCK_SIZE && px + py < (int)x.size() + (int)y.size()) {
        while(px < (int)x.size() && f[x[px].second]) {
            ++px;
        }
        while(py < (int)y.size() && f[y[py].second]) {
            ++py;
        }
        if(px < (int)x.size() && (py == (int)y.size() || x[px].first > y[py].first + 1)) {
            f[x[px].second] = 1;
            z.push_back(x[px++]);
        } else if(py < (int)y.size()) {
            f[y[py].second] = 1;
            z.push_back({y[py].first + 1, y[py++].second});
        }
    }
    for(auto [D, x] : z) {
        f[x] = 0;
    }
    return z;
}

signed main() {
#define TASK "code"

    if (fopen(TASK ".inp", "r")) {
        freopen(TASK ".inp", "r", stdin);
        freopen(TASK ".out", "w", stdout);
    }

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin >> N >> M >> Q;
    for(int i = 1; i <= M; i++) {
        int u, v;
        cin >> u >> v;
        adj[v].emplace_back(u);
    }
    for(int u = 1; u <= N; u++) {
        dp[u].emplace_back(0, u);
        for(int v : adj[u])
            dp[u] = merge_vector(dp[u], dp[v]);
    }
    while(Q--) {
        int u;
        cin >> u;
        int sz;
        cin >> sz;
        vector<int> a(sz, 0);
        for(int &x : a) cin >> x;
        for(int x : a) is_deleted[x] = true;
        if(a.size() >= BLOCK_SIZE) {
            int ans = -1;
            for(int i = 1; i <= N; i++) dist[i] = -1;
            dist[1] = 0;
            for(int i = 2; i <= N; i++) {
                for(int v : adj[i])
                    if(is_deleted[v] == false) {
                        dist[i] = max(dist[i], dist[v] + 1);
                    }
            }
            cout << dist[u] << "\n";
        } else {
            int ans = -1;
            for(auto [x, y] : dp[u]) {
                if(is_deleted[y] == false) ans = max(ans, x);
            }
            cout << ans << "\n";
        }
        for(int x : a) is_deleted[x] = false;
    }
    return (0 ^ 0);
}

Compilation message (stderr)

bitaro.cpp: In function 'std::vector<std::pair<int, int> > merge_vector(std::vector<std::pair<int, int> >&, std::vector<std::pair<int, int> >&)':
bitaro.cpp:30:47: warning: operation on 'py' may be undefined [-Wsequence-point]
   30 |             z.push_back({y[py].first + 1, y[py++].second});
      |                                             ~~^~
bitaro.cpp: In function 'int main()':
bitaro.cpp:71:17: warning: unused variable 'ans' [-Wunused-variable]
   71 |             int ans = -1;
      |                 ^~~
bitaro.cpp:43:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |         freopen(TASK ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
bitaro.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen(TASK ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 86