Submission #677156

#	Time	Username	Problem	Language	Result	Execution time	Memory
677156		stanislavpolyn	Homework (CEOI22_homework)	C++17	53 / 100	334 ms	392032 KiB

Main

#include <bits/stdc++.h>

#define fr(i, a, b) for (int i = (a); i <= (b); ++i)
#define rf(i, a, b) for (int i = (a); i >= (b); --i)
#define fe(x, y) for (auto& x : y)

#define fi first
#define se second
#define pb push_back
#define mp make_pair
#define mt make_tuple

#define all(x) (x).begin(), (x).end()
#define pw(x) (1LL << (x))
#define sz(x) (int)(x).size()

using namespace std;

mt19937_64 rng(228);

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <typename T>
using oset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define fbo find_by_order
#define ook order_of_key

template <typename T>
bool umn(T& a, T b) {
    return a > b ? (a = b, 1) : 0;
}
template <typename T>
bool umx(T& a, T b) {
    return a < b ? (a = b, 1) : 0;
}

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
template <typename T>
using ve = vector<T>;

#ifndef LOCAL
const int N = 5e6 + 5;
#else
const int N = 1005;
#endif

string s;
int last[N];
int p[N];
int root;
ve<int> g[N];
int n;
ve<int> pos;
int val[N];
ve<int> ver;
ve<int> order;
int sz[N];
int inc[N];

void dfs(int v) {
    if (sz(g[v]) == 0) {
        sz[v] = 1;
    }
    fe (to, g[v]) {
        dfs(to);
        sz[v] += sz[to];
    }
    order.pb(v);
}

pii dp[N][2];

int L, R;

void DFS(int v) {
    if (!sz(g[v])) {
        inc[L]++;
        inc[R + 1]--;
        return;
    }

    int to1 = g[v][0];
    int to2 = g[v][1];

    if (s[v - 1] == 'x') {
        L += sz[to1] - dp[to1][0].se;
        R += sz[to1] - dp[to1][0].fi;
        DFS(to2);
        L -= sz[to1] - dp[to1][0].se;
        R -= sz[to1] - dp[to1][0].fi;
    } else {
        L += dp[to1][1].fi;
        R += dp[to1][1].se;
        DFS(to2);
        L -= dp[to1][1].fi;
        R -= dp[to1][1].se;
    }
    swap(to1, to2);
    if (s[v - 1] == 'x') {
        L += sz[to1] - dp[to1][0].se;
        R += sz[to1] - dp[to1][0].fi;
        DFS(to2);
        L -= sz[to1] - dp[to1][0].se;
        R -= sz[to1] - dp[to1][0].fi;
    } else {
        L += dp[to1][1].fi;
        R += dp[to1][1].se;
        DFS(to2);
        L -= dp[to1][1].fi;
        R -= dp[to1][1].se;
    }
}

int main() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
    ios::sync_with_stdio(0);
    cin.tie(0);
#endif

    cin >> s;

    last[0] = -1;
    int bal = 0;
    fr (i, 0, sz(s) - 1) {
        if (s[i] == '(' || s[i] == ')') {
            if (s[i] == '(') {
                bal++;
            } else {
                bal--;
            }
            if (s[i] == '(') {
                p[i] = last[bal - 1];
                last[bal] = i;
            }
        }
        if (s[i] == '?') {
            pos.pb(i);
            p[i] = last[bal];
            n++;
        }
    }

    fr (i, 0, sz(s) - 1) {
        if (s[i] == '(' || s[i] == '?') {
            if (p[i] == -1) {
                root = i;
            } else {
                g[p[i]].pb(i);
            }
            ver.pb(i);
//            cout << i << " " << s[i - 1] << "\n";
        }
    }

    dfs(root);

    {
        fe (v, order) {
            if (sz(g[v]) == 0) {
                dp[v][0] = {0, 0};
                dp[v][1] = {0, 0};
                continue;
            }
            int to1 = g[v][0];
            int to2 = g[v][1];

            if (s[v - 1] == 'x') {
                dp[v][0] = {dp[to1][0].fi + dp[to2][0].fi, dp[to1][0].se + dp[to2][0].se};

                dp[v][1] = {1e9, -1e9};
                umn(dp[v][1].fi, dp[to1][1].fi + dp[to2][1].fi);
                umn(dp[v][1].fi, dp[to1][1].fi + (sz[to2] - dp[to2][0].se));
                umn(dp[v][1].fi, (sz[to1] - dp[to1][0].se) + dp[to2][1].fi);

                umx(dp[v][1].se, dp[to1][1].se + dp[to2][1].se);
                umx(dp[v][1].se, dp[to1][1].se + (sz[to2] - dp[to2][0].fi));
                umx(dp[v][1].se, (sz[to1] - dp[to1][0].fi) + dp[to2][1].se);
            } else {
                dp[v][1] = {dp[to1][1].fi + dp[to2][1].fi, dp[to1][1].se + dp[to2][1].se};

                dp[v][0] = {1e9, -1e9};
                umn(dp[v][0].fi, dp[to1][0].fi + dp[to2][0].fi);
                umn(dp[v][0].fi, dp[to1][0].fi + (sz[to2] - dp[to2][1].se));
                umn(dp[v][0].fi, (sz[to1] - dp[to1][1].se) + dp[to2][0].fi);

                umx(dp[v][0].se, dp[to1][0].se + dp[to2][0].se);
                umx(dp[v][0].se, dp[to1][0].se + (sz[to2] - dp[to2][1].fi));
                umx(dp[v][0].se, (sz[to1] - dp[to1][1].fi) + dp[to2][0].se);
            }
        }
    }

//    cout << dp[3][0].fi << " " << dp[3][0].se << " " << dp[3][1].fi << " " << dp[3][1].se << "\n";

    {

        DFS(root);

//        fr (x, 1, n) {
//        fr (me, 0, sz(pos) - 1) {
//            int v = pos[me];
//
//            int L = 0;
//            int R = 0;
//
////            cout << "start " << v << "\n";
//
//            int last = -1;
//            while (1) {
//                if (sz(g[v])) {
//
////                    cout << "GO " << v << "\n";
//                    int to1 = g[v][0];
//                    int to2 = g[v][1];
//
//                    if (to1 == last) swap(to1, to2);
//
//                    if (s[v - 1] == 'x') {
//                        L += sz[to1] - dp[to1][0].se;
//                        R += sz[to1] - dp[to1][0].fi;
//                    } else {
//                        L += dp[to1][1].fi;
//                        R += dp[to1][1].se;
//                    }
////                    cout << "dp: " << dp[to1][1].se << "\n";
////                    cout << "to1: " << to1 << "\n";
////                    cout << "l, r: " << L << " " << R << "\n";
//                }
//
//                if (v == root) break;
//                last = v;
//                v = p[v];
//            }
//
////            cout << pos[me] << " " << L << " " << R << "\n";
//            inc[L]++;
//            inc[R + 1]--;
//        }

        fr (i, 1, n) inc[i] += inc[i - 1];


        int ans = 0;
        fr (i, 0, n - 1) {
            if (inc[i]) {
                ans++;
            }
        }
        cout << ans << "\n";
    }

    return 0;

    ve<bool> possib(n + 1);

    fr (mask, 0, pw(n - 1) - 1) {
        fr (me, 0, sz(pos) - 1) {
            fe (x, ver) val[x] = -1;

            int x = 1;
            int ptr = 0;
            fr (i, 0, n - 2) {
                if (ptr == me) ptr++;

                if (mask & pw(i)) {
                    val[pos[ptr++]] = 1;
                } else {
                    val[pos[ptr++]] = 0;
                    x++;
                }
            }

            val[pos[me]] = 2;

            bool bad = 0;
            fe (v, order) {
                if (s[v] == '?') continue;

                assert(val[v] == -1);

                if (val[g[v][1]] == 2) swap(g[v][0], g[v][1]);

                if (val[g[v][0]] == 2) {
                    if (s[v - 1] == 'x' && val[g[v][1]] == 1) {
                        bad = 1;
                        break;
                    }
                    if (s[v - 1] == 'n' && val[g[v][1]] == 0) {
                        bad = 1;
                        break;
                    }
                    val[v] = 2;
                } else {
                    if (s[v - 1] == 'x') {
                        val[v] = max(val[g[v][0]], val[g[v][1]]);
                    } else {
                        val[v] = min(val[g[v][0]], val[g[v][1]]);
                    }
                }
            }

            if (!bad) {
                possib[x] = 1;
            }
        }
    }

    int ans = 0;
    fr (i, 1, n) {
        if (possib[i]) {
//            cout << i << "\n";
            ans++;
        }
    }
    cout << ans << "\n";

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 13 / 13
• Subtask 3: 0 / 13
• Subtask 4: 30 / 30
• Subtask 5: 0 / 34