Submission #1046255

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046255		RecursiveCo	Longest Trip (IOI23_longesttrip)	C++17	70 / 100	61 ms	708 KiB

longesttrip

// CF template, version 3.0

#include <bits/stdc++.h>
#include "longesttrip.h"

using namespace std;

#define improvePerformance ios_base::sync_with_stdio(false); cin.tie(0)
#define getTest int t; cin >> t
#define eachTest for (int _var=0;_var<t;_var++)
#define get(name) int (name); cin >> (name)
#define out(o) cout << (o)
#define getList(cnt, name) vector<int> (name); for (int _=0;_<(cnt);_++) { get(a); (name).push_back(a); }
#define sortl(name) sort((name).begin(), (name).end())
#define rev(name) reverse((name).begin(), (name).end())
#define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
#define decision(b) if (b){out("YES");}else{out("NO");}

//#define int long long int

template <typename T, typename I>
struct segtree {
    int n;
    vector<T> tree;
    vector<I> initial;
    T id;

    segtree(int i_n, vector<I> i_initial, T i_id): n(i_n), initial(i_initial), id(i_id) {
        tree.resize(4 * n);
    }

    T conquer(T left, T right) {
        // write your conquer function
    }

    T value(I inp) {
        // write your value function
    }

    void build(int v, int l, int r) {
        if (l == r) tree[v] = value(initial[l]);
        else {
            int middle = (l + r) / 2;
            build(2 * v, l, middle);
            build(2 * v + 1, middle + 1, r);
            tree[v] = conquer(tree[2 * v], tree[2 * v + 1]);
        }
    }

    void upd(int v, int l, int r, int i, I x) {
        if (l == r) tree[v] = value(x);
        else {
            int middle = (l + r) / 2;
            if (middle >= i) upd(2 * v, l, middle, i, x);
            else upd(2 * v + 1, middle + 1, r, i, x);
            tree[v] = conquer(tree[2 * v], tree[2 * v + 1]);
        }
    }

    T query(int v, int l, int r, int ql, int qr) {
        if (ql <= l && r <= qr) return tree[v];
        else if (r < ql || qr < l) return id;
        int middle = (l + r) / 2;
        T left = query(2 * v, l, middle, ql, qr);
        T right = query(2 * v + 1, middle + 1, r, ql, qr);
        return conquer(left, right);
    }
};

// vector<int>

// Find the first node in Y (if any) connected to at least one node in X.
int bin_search(vector<int> A, vector<int> Y) {
    int M = Y.size();
    int l = 0;
    int r = M;
    while (r - l >= 1) {
        int middle = (l + r) / 2;
        vector<int> B;
        forto(middle + 1, i) B.push_back(Y[i]);
        if (are_connected(A, B)) r = middle;
        else l = middle + 1;
    }
    if (l == M) return -1;
    return Y[l];
}

vector<int> longest_trip(int N, int _D) {
    vector<int> path;
    vector<bool> other(N, true); // think of this as "free".
    vector<int> A1;
    A1.push_back(0);
    vector<int> B1;
    forto(N, i) if (i) B1.push_back(i);
    int initial = bin_search(A1, B1);
    if (initial == -1) {
        return B1;
    }
    path.push_back(0);
    path.push_back(initial);
    other[0] = other[initial] = false;
    while (path.size() < N) {
        vector<int> A2;
        vector<int> B2;
        A2.push_back(path[0]);
        B2.push_back(path.back());
        if (are_connected(A2, B2)) {
            vector<int> remain;
            forto(N, i) if (other[i]) remain.push_back(i);
            int first = bin_search(B2, remain);
            if (first == -1) {
                int firsthere = bin_search(remain, path);
                if (firsthere == -1) {
                    if (path.size() >= (N + 1) / 2) return path;
                    return remain;
                }
                vector<int> A3;
                A3.push_back(firsthere);
                int firstout = bin_search(A3, remain);
                vector<int> newpath;
                for (int r: remain) if (r != firstout) newpath.push_back(r);
                newpath.push_back(firstout);
                int ind;
                int s = path.size();
                forto(s, i) if (path[i] == firsthere) ind = i;
                for (int i = ind; i < s; i++) newpath.push_back(path[i]);
                forto(ind, i) newpath.push_back(path[i]);
                return newpath;
            } else {
                path.push_back(first);
                other[first] = false;
            }
        } else {
            int last;
            forto(N, i) if (other[i]) last = i;
            vector<int> A3;
            vector<int> B3;
            A3.push_back(path[0]);
            B3.push_back(last);
            if (are_connected(A3, B3)) {
                rev(path);
                path.push_back(last);
            } else {
                path.push_back(last);
            }
            other[last] = false;
        }
    }
    return path;
}

Compilation message (stderr)

longesttrip.cpp: In function 'int bin_search(std::vector<int>, std::vector<int>)':
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:80:9: note: in expansion of macro 'forto'
   80 |         forto(middle + 1, i) B.push_back(Y[i]);
      |         ^~~~~
longesttrip.cpp: In function 'std::vector<int> longest_trip(int, int)':
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:94:5: note: in expansion of macro 'forto'
   94 |     forto(N, i) if (i) B1.push_back(i);
      |     ^~~~~
longesttrip.cpp:102:24: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  102 |     while (path.size() < N) {
      |            ~~~~~~~~~~~~^~~
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:109:13: note: in expansion of macro 'forto'
  109 |             forto(N, i) if (other[i]) remain.push_back(i);
      |             ^~~~~
longesttrip.cpp:114:37: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  114 |                     if (path.size() >= (N + 1) / 2) return path;
      |                         ~~~~~~~~~~~~^~~~~~~~~~~~~~
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:125:17: note: in expansion of macro 'forto'
  125 |                 forto(s, i) if (path[i] == firsthere) ind = i;
      |                 ^~~~~
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:127:17: note: in expansion of macro 'forto'
  127 |                 forto(ind, i) newpath.push_back(path[i]);
      |                 ^~~~~
longesttrip.cpp:16:35: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   16 | #define forto(name, var) for (int (var) = 0; (var) < (name); (var)++)
      |                                   ^
longesttrip.cpp:135:13: note: in expansion of macro 'forto'
  135 |             forto(N, i) if (other[i]) last = i;
      |             ^~~~~
longesttrip.cpp:123:21: warning: 'ind' may be used uninitialized in this function [-Wmaybe-uninitialized]
  123 |                 int ind;
      |                     ^~~

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 30 / 60