Submission #1019537

#	Time	Username	Problem	Language	Result	Execution time	Memory
1019537		vjudge1	Zagrade (COI17_zagrade)	C++17	10 / 100	3073 ms	45920 KiB

zagrade

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

#define ll long long
#define ld long double
#define ull unsigned long long
#define pii pair<int,int>
#define pll pair<long long, long long>
#define fi first
#define se second
#define all(a) (a).begin(), (a).end()
#define pb push_back
#define lwb lower_bound
#define upb upper_bound

#define TASKNAME "NAME"

void init()
{
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    ///freopen(TASKNAME".INP","r",stdin); freopen(TASKNAME".OUT","w",stdout);
}

const int SZ = 3e5+5, OFFSET = 3e5;
const ll INF = INT_MAX / 2, MOD = 1e9+7, INFLL = 2e18;
const double epsilon = 1e-3;

int n, a[SZ];
string s;
vector<int> adj[SZ];
ll res = 0;
bool del[SZ];

void dfsSize(int u, int pre)
{
    s[u] = 1;
    for(int v : adj[u])
    {
        if(v == pre || del[v]) continue;
        dfsSize(v,u);
        s[u] += s[v];
    }
}

int findCentroid(int u, int pre, int treeSize)
{
    for(int v : adj[u])
    {
        if(v == pre || del[v]) continue;
        if(s[v] > treeSize / 2) return findCentroid(v, u, treeSize);
    }
    return u;
}
int cnt[SZ + SZ];
vector<int> cur;

void dfs(int u, int pre, int root, int sum, int mn1, int mn2)
{
    if(mn2 >= 0) cur.pb(sum);
    if(mn1 == sum)
    {
        res += 1LL * cnt[-sum];
    }
//    if(root == 2)
//    {
//        cout << u << " " << sum << " " << mn1 << " " << mn2 << '\n';
//    }
    if(sum == 0)
    {
        if(mn1 >= 0) res++;
        //if(mn1 >= 0 && root == 2) cout << "a\n";
    }
    for(int v : adj[u])
    {
        if(del[v] || v == pre) continue;
        dfs(v, u, root, sum + a[v], min(mn1, sum + a[v]), min(a[v], a[v] + mn2));
    }
}

vector<int> vec;

void updateRes(int root)
{
    while(!vec.empty())
    {
        cnt[vec.back()]--;
        vec.pop_back();
    }
    for(int u : adj[root])
    {
        if(del[u]) continue;
        int sum = a[root], mn = a[root];
        dfs(u, root, root, sum + a[u], min(mn, sum + a[u]), min(a[u], a[u] + mn));
        while(!cur.empty())
        {
            cnt[cur.back() - a[root]]++;
            vec.pb(cur.back() - a[root]);
            cur.pop_back();
        }
    }
}

void solve(int u)
{
    dfsSize(u,0);
    int root = findCentroid(u, 0, s[u]);
    del[root] = true;
    ll preres = res;
    updateRes(root);
    //cout << root << " - " << res - preres << '\n';
    for(int v : adj[root])
    {
        if(del[v]) continue;
        solve(v);
    }
}

int main()
{
    init();
    cin >> n >> s;
    for(int i = 0; i < s.length(); i++)
    {
        if(s[i] == '(') a[i+1] = 1;
        else a[i+1] = -1;
    }
    for(int i = 1; i < n; i++)
    {
        int u,v;
        cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
    solve(1);
    for(int i = 1; i <= n; i++)
    {
        if(a[i] == 1) a[i] = -1;
        else a[i] = 1;
    }
    memset(del, false, sizeof(del));
    cur.clear();
    solve(1);
    cout << res;
}

Compilation message (stderr)

zagrade.cpp: In function 'void solve(int)':
zagrade.cpp:108:8: warning: unused variable 'preres' [-Wunused-variable]
  108 |     ll preres = res;
      |        ^~~~~~
zagrade.cpp: In function 'int main()':
zagrade.cpp:122:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  122 |     for(int i = 0; i < s.length(); i++)
      |                    ~~^~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 30
• Subtask 3: 0 / 60