Submission #81895

#	Time	Username	Problem	Language	Result	Execution time	Memory
81895		aquablitz11	Port Facility (JOI17_port_facility)	C++14	22 / 100	35 ms	1328 KiB

port_facility

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

using pii = pair<int, int>;
#define x first
#define y second

const int N = 2010;
const int MOD = 1e9+7;

int n, ans = 1;
pii A[N];
pii ev[N*2];
int col[N];

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)
{
    for (int j = 0; j < n; ++j) {
        if (intersect(A[i].x, A[i].y, A[j].x, A[j].y)) {
            if (col[j] != 0)
                continue;
            col[j] = col[i] == 1 ? 2 : 1;
            solve(j);
        }
    }
}

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-1] = pii(i, 1);
        ev[A[i].y-1] = pii(i, 2);
    }
    for (int i = 0; i < n && ans != 0; ++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:38:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
port_facility.cpp:40:14: 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: 0 / 56
• Subtask 4: 0 / 22