Submission #1119843

#	Time	Username	Problem	Language	Result	Execution time	Memory
1119843		Yang8on	Synchronization (JOI13_synchronization)	C++17	100 / 100	270 ms	33284 KiB

synchronization

#include <bits/stdc++.h>
#define Y8o "Synchronization"
#define maxn (int) 2e5 + 5
#define ll long long
#define pii pair<ll, ll>
#define gb(i, j) ((i >> j) & 1)
#define all(x) x.begin(), x.end()
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define fi(i, a, b) for(int i = a; i <= b; i ++)
#define fid(i, a, b) for(int i = a; i >= b; i --)

//#define f first
//#define s second

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
    return uniform_int_distribution<ll> (l, r) (rng);
}
void iof() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL), cout.tie(NULL);
    if(fopen(Y8o".inp", "r"))
    {
        freopen(Y8o".inp", "r", stdin);
//        freopen(Y8o".out", "w", stdout);
    }
}
void ctime() {
    cerr << "\n" << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}

int n, m, Q;
vector<int> o[maxn];
int a[maxn], c[maxn];
int in[maxn], out[maxn], cnt;
int h[maxn], cha[maxn][20];
struct dl { int u, v, id; } ed[maxn];

void dfs(int u = 1, int p = 0) {
    in[u] = ++cnt;
    for(int v : o[u]) if(v != p) {
        h[v] = h[u] + 1, cha[v][0] = u;
        fi(i, 1, 17) cha[v][i] = cha[ cha[v][i - 1] ][i - 1];
        dfs(v, u);
    }
    out[u] = cnt;
}
struct BIT {
    int bit[maxn];
    void update(int x, int val) {
        while(x <= n) bit[x] += val, x += (x & -x);
    }
    int get(int x, int best = 0) {
        while(x > 0) best += bit[x], x -= (x & -x);
        return best;
    }
} Bit;

int par(int u) {
    fid(i, 17, 0) {
        if(cha[u][i] && Bit.get(in[u]) == Bit.get(in[cha[u][i]])) u = cha[u][i];
    }
    return u;
}

void solve() {
    cin >> n >> m >> Q;
    fi(i, 1, n - 1) {
        int u, v; cin >> u >> v;
        o[u].push_back(v), o[v].push_back(u);
        ed[i] = { u, v, 0 };
    }
    dfs();

    fi(i, 1, n - 1) {
        int &u = ed[i].u, &v = ed[i].v;
        if(cha[u][0] == v) swap(u, v);
        Bit.update(in[v], -1), Bit.update(out[v] + 1, +1);
    }

    fi(i, 1, n) a[i] = 1, c[i] = 0;
    fi(i, 1, m) {
        int pos; cin >> pos;
        int u = ed[pos].u, v = ed[pos].v, &id = ed[pos].id;
        if(!id) {
            a[par(u)] += a[v] - c[v];
            Bit.update(in[v], +1), Bit.update(out[v] + 1, -1);
        }
        else {
            a[v] = c[v] = a[par(u)];
            Bit.update(in[v], -1), Bit.update(out[v] + 1, +1);
        }
        id ^= 1;
    }

    fi(i, 1, Q) {
        int u; cin >> u;
        cout << a[par(u)] << '\n';
    }
}

int main() {
    iof();

    int nTest = 1;
//    cin >> nTest;

    while(nTest --) {
        solve();
    }

    ctime();
    return 0;
}

Compilation message (stderr)

synchronization.cpp: In function 'void iof()':
synchronization.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(Y8o".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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