Submission #708180

#	Time	Username	Problem	Language	Result	Execution time	Memory
708180		device	Memory 2 (JOI16_memory2)	C++17	60 / 100	1 ms	340 KiB

memory2

#include <bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y){
    return uniform_int_distribution<int>(x, y)(rng);
}
int Flip(int I, int J);
void Answer(int I, int J, int X);
void out(int i, int j, int k) {
    if (i > j) swap(i, j);
    Answer(i, j, k);
}
void Solve(int t, int n){
    vector<int> v;
    for (int i = 0; i < (n << 1); i++) v.push_back(i);
    while (!v.empty()) {
        vector<vector<int>> p(n);
        int ptr = v[rnd(0, v.size()-1)], it;
        for (int i = 0; i < v.size(); i++) if (v[i] != ptr) p[Flip(ptr, v[i])].push_back(v[i]);
        for (int i = 0; i < n; i++) {
            if (p[i].size() == 2) {
                v.erase(find(v.begin(), v.end(), p[i][0]));
                v.erase(find(v.begin(), v.end(), p[i][1]));
                out(p[i][0], p[i][1], i);
            } else if (p[i].size() & 1) it = i;
        }
        if (v.size() == 2) {
            out(v[0], v[1], it);
            return;
        }
    }
}

Compilation message (stderr)

memory2.cpp: In function 'void Solve(int, int)':
memory2.cpp:19:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 |         for (int i = 0; i < v.size(); i++) if (v[i] != ptr) p[Flip(ptr, v[i])].push_back(v[i]);
      |                         ~~^~~~~~~~~~
memory2.cpp:11:11: warning: 'it' may be used uninitialized in this function [-Wmaybe-uninitialized]
   11 |     Answer(i, j, k);
      |     ~~~~~~^~~~~~~~~
memory2.cpp:18:42: note: 'it' was declared here
   18 |         int ptr = v[rnd(0, v.size()-1)], it;
      |                                          ^~

• Subtask 1: 10 / 10
• Subtask 2: 50 / 50
• Subtask 3: 0 / 40