Submission #1026520

#	Time	Username	Problem	Language	Result	Execution time	Memory
1026520		Whisper	Zagrade (COI17_zagrade)	C++17	100 / 100	754 ms	56552 KiB

zagrade

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, n) for (int i = 0; i < (a); ++i)
#define REPD(i, n) for (int i = (a) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX         300005
int numNode;
string s;
vector<int> G[MAX];

int sz[MAX], del[MAX], label[MAX];

void reSubsize(int u, int p = -1){
    sz[u] = 1;
    for (int &v : G[u]) if(v ^ p){
        if (del[v]) continue;
        reSubsize(v, u);
        sz[u] += sz[v];
    }
}

int findCentroid(int u, int p, int siz){
    for (int &v : G[u]) if(v ^ p){
        if(del[v]) continue;
        if (2 * sz[v] > siz) return findCentroid(v, u, siz);
    }
    return u;
}
map<int, int> cnt;

int ans = 0;
void dfs(int u, int p, int pref, int mxpref, int mnpref, bool add){
    pref += label[u]; maximize(mxpref, pref); minimize(mnpref, pref);
    if(add){
        if (-pref + mxpref <= 0 && pref >= 0){
            cnt[pref]++;
        }
    }
    else{
        if (-pref + mnpref >= 0){
            assert(pref <= 0);
            ans += 1LL * cnt[-pref];
        }
    }

    for (int&v : G[u]) if(v ^ p){
        if (!del[v]) {
            dfs(v, u, pref, mxpref, mnpref, add);
        }
    }
}
void decompose(int root){
    reSubsize(root);
    int siz = sz[root];
    root = findCentroid(root, root, siz);

    cnt.clear();
    del[root] = 1;
    if(label[root] != -1) cnt[label[root]]++;
    for (int&v : G[root]) if(!del[v]){
        dfs(v, root, 0, 0, 0, 0);
        dfs(v, root, label[root], label[root], label[root], 1);
    }

    ans += 1LL * cnt[0];
    cnt.clear();
    reverse(G[root].begin(), G[root].end());

    for (int&v : G[root]) if(!del[v]){
        dfs(v, root, 0, 0, 0, 0);
        dfs(v, root, label[root], label[root], label[root], 1);
    }
    for (int&v : G[root]) if(!del[v]){
        decompose(v);
    }
}
void process(void){
    cin >> numNode >> s;
    for (int i = 1; i <= numNode; ++i) label[i] = (s[i - 1] == '(' ? 1 : -1);

    for (int i = 1; i < numNode; ++i){
        int u, v; cin >> u >> v;
        G[u].emplace_back(v);
        G[v].emplace_back(u);
    }
    decompose(1);
    cout << ans;
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    process();
    return (0 ^ 0);
}

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