Submission #723342

#	Time	Username	Problem	Language	Result	Execution time	Memory
723342		kkts	Synchronization (JOI13_synchronization)	C++14	100 / 100	308 ms	38140 KiB

synchronization

#include<bits/stdc++.h>
#define f first
#define s second
#define int long long
#define pii pair<int,int>
using namespace std;
const int N = 2e5 + 5, mod = 1e9 + 7; // !
int timer, out[N], in[N], p[N][20], t[N], ans[N], last[N], f[N];
int n;
pair<int,int> e[N];
vector<int> V[N];
void dfs(int u) {
    in[u] = ++timer;
    for(int i = 1; i <= 18; i++) p[u][i] = p[p[u][i - 1]][i - 1];
    for(int i = 0; i < V[u].size(); i++) {
        if(V[u][i] != p[u][0]) p[V[u][i]][0] = u, dfs(V[u][i]);
    }
    out[u] = timer;
}
void upd(int id, int v) {
    for(id; id <= n; id += id & (-id)) t[id] += v;
}
int get(int id) {
    int ans = 0;
    for(id; id >= 1; id -= id & (-id)) ans += t[id];
    return ans;
}
int up(int u) {
    int x = get(in[u]);
    for(int i = 18; i >= 0; i--) {
        if(p[u][i] && x == get(in[p[u][i]])) u = p[u][i];
    }
    return u;
}
main(){
    ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    int m, q;
    cin >> n >> m >> q;
    ans[n] = 1;
    for(int i = 1; i < n; i++) {
        int u, v; cin >> u >> v;
        V[u].push_back(v);
        V[v].push_back(u);
        e[i] = {u, v};
        ans[i] = 1;
    }
    dfs(1);
    for(int i = 1; i <= n; i++)
    upd(in[i], 1), upd(out[i] + 1, -1);
    while(m--) {
        int x;
        cin >> x;
        int u = e[x].f;
        if(p[e[x].s][0] == u) u = e[x].s;

        if(f[x]) {
            int root = up(u);
            f[x] = 0;
            last[x] = ans[u] = ans[root];
            upd(in[u], 1); upd(out[u] + 1, -1);
        } else {
            f[x] = 1;
            u = e[x].s + e[x].f - u;
            int root = up(u);
            ans[root] = ans[root] + ans[e[x].s + e[x].f - u] - last[x];
            upd(in[e[x].s + e[x].f - u], -1); upd(out[e[x].s + e[x].f - u] + 1, 1);
        }

    }

    while(q--) {
        int x; cin >> x;
        cout << ans[up(x)] << "\n";
    }
}

Compilation message (stderr)

synchronization.cpp: In function 'void dfs(long long int)':
synchronization.cpp:15:22: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |     for(int i = 0; i < V[u].size(); i++) {
      |                    ~~^~~~~~~~~~~~~
synchronization.cpp: In function 'void upd(long long int, long long int)':
synchronization.cpp:21:9: warning: statement has no effect [-Wunused-value]
   21 |     for(id; id <= n; id += id & (-id)) t[id] += v;
      |         ^~
synchronization.cpp: In function 'long long int get(long long int)':
synchronization.cpp:25:9: warning: statement has no effect [-Wunused-value]
   25 |     for(id; id >= 1; id -= id & (-id)) ans += t[id];
      |         ^~
synchronization.cpp: At global scope:
synchronization.cpp:35:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   35 | main(){
      | ^~~~

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