제출 #1328520

#제출 시각아이디문제언어결과실행 시간메모리
1328520wedonttalkanymorePort Facility (JOI17_port_facility)C++20
100 / 100
1539 ms494972 KiB
#include <bits/stdc++.h>
/*
    Chang ki si xuyen man dem
    Di lac vao trong giac mong
*/
using namespace std;
using ll = long long;

#define int long long
#define pii pair<ll, ll>
#define fi first
#define se second

const ll N = 2e6 + 5, inf = 1e18, mod = 1e9 + 7, block = 320, lim = 19;

int n;
pii a[N];
int L[N], R[N];

struct ST {
    pii st[4 * N], st1[4 * N];
    void update(int i, int l, int r, int pos, pii val) {
        if (l == r) {
            st[i] = val;
            st1[i] = val;
            return;
        }
        int mid = (l + r) / 2;
        if (pos <= mid) update(2 * i, l, mid, pos, val);
        else update(2 * i + 1, mid + 1, r, pos, val);
        if (st[2 * i].fi <= st[2 * i + 1].fi) {
            st[i] = st[2 * i];
        }
        else {
            st[i] = st[2 * i + 1];
        }
        if (st1[2 * i].fi <= st1[2 * i + 1].fi) {
            st1[i] = st1[2 * i + 1];
        }
        else {
            st1[i] = st1[2 * i];
        }
    }
    pii get1(int i, int l, int r, int u, int v) { // tim con min
        if (u > r || v < l) return make_pair(inf, 0);
        if (u <= l && r <= v) return st[i];
        int mid = (l + r) / 2;
        pii L = get1(2 * i, l, mid, u, v);
        pii R = get1(2 * i + 1, mid + 1, r, u, v);
        if (L.fi <= R.fi) return L;
        else return R;
    }
    pii get2(int i, int l, int r, int u, int v) { // tim con max
        if (u > r || v < l) return make_pair(0, 0);
        if (u <= l && r <= v) return st1[i];
        int mid = (l + r) / 2;
        pii L = get2(2 * i, l, mid, u, v);
        pii R = get2(2 * i + 1, mid + 1, r, u, v);
        if (L.fi <= R.fi) return R;
        else return L;
    }
} st, st1;

vector <int> adj[N];
int color[N];
int vst[N];
bool ok = 1;

void dfs(int u) {
    // cout << u << '\n';
    vst[u] = 1;
    for (auto v : adj[u]) {
        // if (v == 4) cout << u << '\n';
        if (!vst[v]) {
            color[v] = color[u] ^ 1;
            dfs(v);
        }
        else if (color[u] == color[v]) {
            ok = 0;
            return;
        }
    }
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    if (fopen(".inp", "r")) {
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a[i].fi >> a[i].se;
    }
    sort(a + 1, a + n + 1);
    for (int i = 1; i <= n; i++) {
        L[i] = a[i].fi, R[i] = a[i].se;
    }
    for (int i = 0; i < 4 * N; i++) st.st[i].fi = inf;
    for (int i = 1; i <= n; i++) {
        pii pos = st.get1(1, 1, 2 * n, L[i], R[i]);
        // if (i == 4) cout << pos.se << '\n';
        if (pos.se && pos.fi < L[i]) {
            adj[i].push_back(pos.se);
            adj[pos.se].push_back(i);
        }
        st.update(1, 1, 2 * n, R[i], make_pair(L[i], i));
    }
    for (int i = n; i >= 1; i--) {
        pii pos = st1.get2(1, 1, 2 * n, L[i], R[i]);
        // if (i == 4) cout << pos.se << '\n';
        if (pos.se && pos.fi > R[i]) {
            adj[i].push_back(pos.se);
            adj[pos.se].push_back(i);
        }
        st1.update(1, 1, 2 * n, L[i], make_pair(R[i], i));
    }
    memset(color, -1, sizeof(color));
    int ans = 1;
    for (int i = 1; i <= n; i++) {
        // cout << vst[i] << ' ';
        if (!vst[i]) {
            color[i] = 0;
            ok = 1;
            dfs(i);
            if (ok) ans = (ans * 2) % mod;
            else {
                ans = 0;
                break;
            }
        }
    }
    cout << ans;
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

port_facility.cpp: In function 'int main()':
port_facility.cpp:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
port_facility.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
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