Submission #81984

#	Time	Username	Problem	Language	Result	Execution time	Memory
81984		aquablitz11	Port Facility (JOI17_port_facility)	C++14	78 / 100	6132 ms	616672 KiB

port_facility

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

using pii = pair<int, int>;
#define x first
#define y second
#define all(x) x.begin(), x.end()

const int N = 1<<20;
const int MOD = 1e9+7;

int n;
pii A[N];
pii ev[N<<1];
int col[N];

struct data {
    vector<int> v;
    int ptr;
} seg[N<<2], seg2[N<<2];

void build(int p=1, int b=0, int e=2*n-1)
{
    if (b == e) {
        if (ev[b].y == 1)
            seg[p].v.push_back(A[ev[b].x].y);
    } else {
        int m = (b+e)/2;
        build(p<<1, b, m);
        build(p<<1|1, m+1, e);
        seg[p].v.reserve(seg[p<<1].v.size() + seg[p<<1|1].v.size());
        merge(all(seg[p<<1].v), all(seg[p<<1|1].v), back_inserter(seg[p].v));
    }
    seg[p].ptr = seg[p].v.size()-1;
}

inline int ix(int t) {
    return t < 0 ? -1 : ev[t].x;
}

inline int amort(int p)
{
    while (seg[p].ptr >= 0 && col[ix(seg[p].v[seg[p].ptr])])
        --seg[p].ptr;
    return seg[p].ptr == -1 ? -1 : seg[p].v[seg[p].ptr];
}

int get(int l, int r, int p=1, int b=0, int e=2*n-1)
{
    if (b > r || e < l)
        return -1;
    if (b >= l && e <= r)
        return amort(p);
    int m = (b+e)/2;
    return max(get(l, r, p<<1, b, m), get(l, r, p<<1|1, m+1, e));
}

inline int ix2(int t) {
    return t < 0 ? -1 : ev[2*n-t-1].x;
}

void build2(int p=1, int b=0, int e=2*n-1)
{
    if (b == e) {
        int t = 2*n-b-1;
        if (ev[t].y == 2)
            seg2[p].v.push_back(2*n-A[ev[t].x].x-1);
    } else {
        int m = (b+e)/2;
        build2(p<<1, b, m);
        build2(p<<1|1, m+1, e);
        merge(all(seg2[p<<1].v), all(seg2[p<<1|1].v), back_inserter(seg2[p].v));
    }
    seg2[p].ptr = seg2[p].v.size()-1;
}

inline int amort2(int p)
{
    while (seg2[p].ptr >= 0 && col[ix2(seg2[p].v[seg2[p].ptr])])
        --seg2[p].ptr;
    return seg2[p].ptr == -1 ? -1 : seg2[p].v[seg2[p].ptr];
}

int get2(int l, int r, int p=1, int b=0, int e=2*n-1)
{
    if (b > r || e < l)
        return -1;
    if (b >= l && e <= r)
        return amort2(p);
    int m = (b+e)/2;
    return max(get2(l, r, p<<1, b, m), get2(l, r, p<<1|1, m+1, e));
}

inline bool intersect(int al, int ar, int bl, int br)
{
    if (bl > ar || br < al) return false;
    if (bl >= al && br <= ar) return false;
    if (al >= bl && ar <= br) return false;
    return true;
}

void solve(int i, int lv=0)
{
    //for (int j = 0; j < lv; ++j)
        //printf("| ");
    //printf("solve %d, color = %d\n", i, col[i]);
    while (true) {
        int ans = get(A[i].x, A[i].y);
        int j = ix(ans);
        if (ans == -1 || !intersect(A[i].x, A[i].y, A[j].x, A[j].y))
            break;
        col[j] = col[i] == 1 ? 2 : 1;
        solve(j, lv+1);
    }
    while (true) {
        int ans = get2(2*n-A[i].y-1, 2*n-A[i].x-1);
        int j = ix2(ans);
        if (ans == -1 || !intersect(A[i].x, A[i].y, A[j].x, A[j].y))
            break;
        col[j] = col[i] == 1 ? 2 : 1;
        solve(j, lv+1);
    }
}

int main()
{
    scanf("%d", &n);
    for (int i = 0; i < n; ++i) {
        scanf("%d%d", &A[i].x, &A[i].y);
        ev[--A[i].x] = pii(i, 1);
        ev[--A[i].y] = pii(i, 2);
        //printf("%d: %d %d\n", i, A[i].x, A[i].y);
    }
    build();
    build2();
    int ans = 1;
    for (int i = 0; i < n; ++i) {
        if (!col[i]) {
            col[i] = 1;
            solve(i);
            ans = (ans*2)%MOD;
        }
    }
    stack<int> S[2];
    for (int i = 0; i < 2*n; ++i) {
        int x = ev[i].x, t = ev[i].y;
        int c = col[x]-1;
        if (t == 1)
            S[c].push(x);
        else {
            if (S[c].top() != x) {
                ans = 0;
                break;
            }
            S[c].pop();
        }
    }

    printf("%d\n", ans);

    return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:127:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
port_facility.cpp:129:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &A[i].x, &A[i].y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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