Submission #833985

#	Time	Username	Problem	Language	Result	Execution time	Memory
833985		LucaIlie	Port Facility (JOI17_port_facility)	C++17	78 / 100	6040 ms	226156 KiB

port_facility

#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 1e6;
const int MOD = 1e9 + 7;


int n;
bool bipartit = true;
bool vis[MAX_N], side[MAX_N];
int l[MAX_N], r[MAX_N];
int indexL[2 * MAX_N + 1], indexR[2 * MAX_N + 1];

struct info {
    int minn, maxx;

    info operator + ( info x ) {
        return { min( minn, x.minn ), max( maxx, x.maxx ) };
    }
};

struct SEG_TREE {
    info segTree[4 * MAX_N];

    void init() {
        for ( int v = 0; v < 4 * MAX_N; v++ )
            segTree[v] = { 2 * n + 1, 0 };
    }

    void update( int v, int l, int r, int pos, info x ) {
        if ( l > pos || r < pos )
            return;

        if ( l == r ) {
            segTree[v] = x;
            return;
        }

        int mid = (l + r) / 2;
        update( v * 2 + 1, l, mid, pos, x );
        update( v * 2 + 2, mid + 1, r, pos, x );
        segTree[v] = segTree[v * 2 + 1] + segTree[v * 2 + 2];
    }

    info query( int v, int l, int r, int lq, int rq ) {
        if ( l > rq || r < lq )
            return { 2 * n + 1, 0 };

        if ( lq <= l && r <= rq )
            return segTree[v];

        int mid = (l + r) / 2;
        return query( v * 2 + 1, l, mid, lq, rq ) + query( v * 2 + 2, mid + 1, r, lq, rq );
    }
};

SEG_TREE unvisitedByL, unvisitedByR, visitedByL0, visitedByR0, visitedByL1, visitedByR1;

void checkBipartit( int u ) {
    vis[u] = true;
    unvisitedByL.update( 0, 1, 2 * n, l[u], { 2 * n + 1, 0 } );
    unvisitedByR.update( 0, 1, 2 * n, r[u], { 2 * n + 1, 0 } );
    if ( side[u] == 0 ) {
        visitedByL0.update( 0, 1, 2 * n, l[u], { r[u], r[u] } );
        visitedByR0.update( 0, 1, 2 * n, r[u], { l[u], l[u] } );
    } else {
        visitedByL1.update( 0, 1, 2 * n, l[u], { r[u], r[u] } );
        visitedByR1.update( 0, 1, 2 * n, r[u], { l[u], l[u] } );
    }

    while ( unvisitedByL.query( 0, 1, 2 * n, l[u], r[u] ).maxx > r[u] ) {
        int v = indexR[unvisitedByL.query( 0, 1, 2 * n, l[u], r[u] ).maxx];
        side[v] = side[u] ^ 1;
        checkBipartit( v );
    }
    while ( unvisitedByR.query( 0, 1, 2 * n, l[u], r[u] ).minn < l[u] ) {
        int v = indexL[unvisitedByR.query( 0, 1, 2 * n, l[u], r[u] ).minn];
        side[v] = side[u] ^ 1;
        checkBipartit( v );
    }

    bool exista0 = false, exista1 = false;
    if ( visitedByL0.query( 0, 1, 2 * n, l[u], r[u] ).maxx > r[u] || visitedByR0.query( 0, 1, 2 * n, l[u], r[u] ).minn < l[u] )
        exista0 = true;
    if ( visitedByL1.query( 0, 1, 2 * n, l[u], r[u] ).maxx > r[u] || visitedByR1.query( 0, 1, 2 * n, l[u], r[u] ).minn < l[u] )
        exista1 = true;

    if ( exista0 && exista1 )
        bipartit = false;
}

int main() {
    cin >> n;
    for ( int i = 0; i < n; i++ )
        cin >> l[i] >> r[i];

    unvisitedByL.init();
    unvisitedByR.init();
    visitedByL0.init();
    visitedByR0.init();
    visitedByL1.init();
    visitedByR1.init();
    for ( int i = 0; i < n; i++ ) {
        unvisitedByL.update( 0, 1, 2 * n, l[i], { r[i], r[i] } );
        unvisitedByR.update( 0, 1, 2 * n, r[i], { l[i], l[i] } );
        indexL[l[i]] = i;
        indexR[r[i]] = i;
    }

    int comp = 0;
    for ( int u = 0; u < n; u++ ) {
        if ( !vis[u] ) {
            side[u] = 0;
            checkBipartit( u );
            comp++;
        }
    }

    if ( bipartit ) {
        int ans = 1;
        for ( int i = 0; i < comp; i++ )
            ans = ans * 2 % MOD;
        cout << ans;
    } else
        cout << 0;

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 56 / 56
• Subtask 4: 0 / 22