Submission #1265823

#	Time	Username	Problem	Language	Result	Execution time	Memory
1265823		icebear	Synchronization (JOI13_synchronization)	C++20	100 / 100	202 ms	26116 KiB

synchronization

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int n, m, q;
vector<int> G[N];
int par[N][20], h[N];
int tin[N], tout[N], timer = 0;
ii edge[N];
int ft[N];

void update(int x, int v) {
    for(; x <= n; x += x & -x) ft[x] += v;
}

int get(int x) {
    int ans = 0;
    for(; x; x -= x & -x) ans += ft[x];
    return ans;
}

int root(int u) {
    RED(j, 20) if (par[u][j] > 0) {
        int tmp = get(tin[u]) - get(tin[par[u][j]]);
        if (!tmp) u = par[u][j];
    }
    return u;
}

void dfs(int u) {
    tin[u] = ++timer;
    for(int v : G[u]) {
        if (v == par[u][0]) continue;
        par[v][0] = u;
        h[v] = h[u] + 1;
        dfs(v);
    }
    tout[u] = timer;
}

void init(void) {
    cin >> n >> m >> q;
    FOR(i, 2, n) {
        int u, v;
        cin >> u >> v;
        G[u].pb(v);
        G[v].pb(u);
        edge[i - 1] = mp(u, v);
    }
}

void process(void) {
    dfs(1);
    FOR(j, 1, 19) FOR(i, 1, n)
        par[i][j] = par[par[i][j - 1]][j - 1];
    FOR(i, 1, n - 1) {
        if (h[edge[i].fi] > h[edge[i].se])
            swap(edge[i].fi, edge[i].se);
        update(tin[edge[i].se], +1);
        update(tout[edge[i].se] + 1, -1);
    }

    vector<bool> state(n, false);
    vector<int> last_contribute(n + 5, 0);
    vector<int> ans(n + 5, 1);
    while(m--) {
        int e; cin >> e;
        int u, v; tie(u, v) = edge[e];
        update(tin[v], (state[e] ? +1 : -1));
        update(tout[v] + 1, (state[e] ? -1 : +1));
        if (state[e] == false) {
            ans[root(v)] += ans[v] - last_contribute[v];
        } else {
            last_contribute[v] = ans[v] = ans[root(u)];
        }
        state[e] = state[e] ^ 1;
    }

    while(q--) {
        int u; cin >> u;
        cout << ans[root(u)] << '\n';
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//     cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'int main()':
synchronization.cpp:122:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
synchronization.cpp:123:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 10 / 10
• Subtask 4: 20 / 20
• Subtask 5: 40 / 40