Submission #1066656

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066656		becaido	Longest Trip (IOI23_longesttrip)	C++17	100 / 100	14 ms	600 KiB

longesttrip

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx,popcnt,sse4,abm")
#include <bits/stdc++.h>
using namespace std;

#ifndef WAIMAI
#include "longesttrip.h"
#else
#include "grader.cpp"
#endif

#ifdef WAIMAI
#define debug(HEHE...) cout << "[" << #HEHE << "] : ", dout(HEHE)
void dout() {cout << '\n';}
template<typename T, typename...U>
void dout(T t, U...u) {cout << t << (sizeof...(u) ? ", " : ""), dout(u...);}
#else
#define debug(...) 7122
#endif

#define ll long long
#define Waimai ios::sync_with_stdio(false), cin.tie(0)
#define FOR(x,a,b) for (int x = a, I = b; x <= I; x++)
#define pb emplace_back
#define F first
#define S second

bool is(int x, int y) {
    return are_connected({x}, {y});
}
vector<int> longest_trip(int n, int D) {
    vector<int> A, B;
    A.pb(0), B.pb(1);
    FOR (i, 2, n - 1) {
        if (i == n - 1) {
            if (is(A.back(), i)) {
                A.pb(i);
                continue;
            }
            if (is(B.back(), i)) {
                B.pb(i);
                continue;
            }
            reverse(B.begin(), B.end());
            A.insert(A.end(), B.begin(), B.end());
            B.clear();
            B.pb(i);
            continue;
        }
        bool ax = is(A.back(), i);
        bool xy = is(i, i + 1);
        if (ax && xy) {
            A.pb(i);
            A.pb(i + 1);
        } else if (ax) {
            bool by = is(B.back(), i + 1);
            if (by) {
                A.pb(i);
                B.pb(i + 1);
            } else {
                A.pb(i);
                reverse(B.begin(), B.end());
                A.insert(A.end(), B.begin(), B.end());
                B.clear();
                B.pb(i + 1);
            }
        } else if (xy) {
            bool bx = is(B.back(), i);
            if (bx) {
                B.pb(i);
                B.pb(i + 1);
            } else {
                reverse(B.begin(), B.end());
                A.insert(A.end(), B.begin(), B.end());
                B.clear();
                B.pb(i);
                B.pb(i + 1);
            }
        } else {
            bool by = is(B.back(), i + 1);
            if (by) {
                A.pb(i + 1);
                reverse(B.begin(), B.end());
                A.insert(A.end(), B.begin(), B.end());
                B.clear();
                B.pb(i);
            } else {
                A.pb(i + 1);
                B.pb(i);
            }
        }
        i++;
    }
    if (is(A[0], B[0])) {
        reverse(A.begin(), A.end());
        A.insert(A.end(), B.begin(), B.end());
        return A;
    }
    if (is(A[0], B.back())) {
        B.insert(B.end(), A.begin(), A.end());
        return B;
    }
    if (is(A.back(), B[0])) {
        A.insert(A.end(), B.begin(), B.end());
        return A;
    }
    if (is(A.back(), B.back())) {
        reverse(B.begin(), B.end());
        A.insert(A.end(), B.begin(), B.end());
        return A;
    }
    if (are_connected(A, B) == 0) return A.size() > B.size() ? A : B;
    int i = -1, j = -1;
    {
        int l = 0, r = A.size() - 1;
        while (l < r) {
            int mid = (l + r) / 2;
            vector<int> Al(A.begin() + l, A.begin() + mid + 1);
            if (are_connected(Al, B)) r = mid;
            else l = mid + 1;
        }
        i = l;
    }
    {
        int l = 0, r = B.size() - 1;
        while (l < r) {
            int mid = (l + r) / 2;
            vector<int> Bl(B.begin() + l, B.begin() + mid + 1);
            if (are_connected({A[i]}, Bl)) r = mid;
            else l = mid + 1;
        }
        j = l;
    }
    vector<int> ans;
    FOR (k, i + 1, A.size() - 1) ans.pb(A[k]);
    FOR (k, 0, i) ans.pb(A[k]);
    FOR (k, j, B.size() - 1) ans.pb(B[k]);
    FOR (k, 0, j - 1) ans.pb(B[k]);
    return ans;
}

/*
in1
2
5 1
1
1 1
0 0 1
0 0 0 1
4 1
1
0 0
0 0 1
out1
5
1 0 2 3 4
4
2
0 1
3
4

in2
out2
*/

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 60 / 60