Submission #1051216

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051216		Trent	Thousands Islands (IOI22_islands)	C++17	8.40 / 100	22 ms	6116 KiB

islands

#include "islands.h"
#include "bits/stdc++.h"
using namespace std;
#define forR(i, x) for(int i = 0; i < (x); ++i)
#define REP(i, a, b) for(int i = (a); i < (b); ++i)
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vll;
typedef vector<bool> vb;

struct edge{int t, i;};
vector<vector<edge>> adj;
vi nStk, eStk;
vb oStk, vis;
bool dfs(int c, vi& ans) {
  // nStk is [0, c), eStk is [0, c]
  if(oStk[c]) {
    int sInd;
    forR(i, nStk.size()) if(nStk[i] == c) sInd = i;
    forR(i, sInd) ans.push_back(eStk[i]);
    REP(i, sInd, eStk.size()) ans.push_back(eStk[i]);
    REP(i, sInd, eStk.size()) ans.push_back(eStk[i] ^ 1);
    REP(i, sInd, eStk.size()) ans.push_back(eStk[i]);
    REP(i, sInd, eStk.size()) ans.push_back(eStk[i] ^ 1);
    for(int i = sInd - 1; i >= 0; --i) ans.push_back(eStk[i]);
    return true;
  }
  if(!vis[c]) {
    vis[c] = true;
    oStk[c] = true;
    nStk.push_back(c);
    for(auto [t, i] : adj[c]) {
      eStk.push_back(i);
      if(dfs(t, ans)) return true;
      eStk.pop_back();
    }
    nStk.pop_back();
    oStk[c] = false;
  }
  return false;
}
std::variant<bool, std::vector<int>> find_journey(
    int N, int M, std::vector<int> U, std::vector<int> V) {
      adj.resize(N);
      forR(i, M) {
        adj[U[i]].push_back({V[i], i});
      }
      oStk.resize(N);
      vis.resize(N);
      vi ans;
      bool done = dfs(0, ans);
      if(done) return ans;
      return false;
}

Compilation message (stderr)

islands.cpp: In function 'bool dfs(int, vi&)':
islands.cpp:4:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    4 | #define forR(i, x) for(int i = 0; i < (x); ++i)
      |                                     ^
islands.cpp:21:5: note: in expansion of macro 'forR'
   21 |     forR(i, nStk.size()) if(nStk[i] == c) sInd = i;
      |     ^~~~
islands.cpp:5:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define REP(i, a, b) for(int i = (a); i < (b); ++i)
      |                                         ^
islands.cpp:23:5: note: in expansion of macro 'REP'
   23 |     REP(i, sInd, eStk.size()) ans.push_back(eStk[i]);
      |     ^~~
islands.cpp:5:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define REP(i, a, b) for(int i = (a); i < (b); ++i)
      |                                         ^
islands.cpp:24:5: note: in expansion of macro 'REP'
   24 |     REP(i, sInd, eStk.size()) ans.push_back(eStk[i] ^ 1);
      |     ^~~
islands.cpp:5:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define REP(i, a, b) for(int i = (a); i < (b); ++i)
      |                                         ^
islands.cpp:25:5: note: in expansion of macro 'REP'
   25 |     REP(i, sInd, eStk.size()) ans.push_back(eStk[i]);
      |     ^~~
islands.cpp:5:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    5 | #define REP(i, a, b) for(int i = (a); i < (b); ++i)
      |                                         ^
islands.cpp:26:5: note: in expansion of macro 'REP'
   26 |     REP(i, sInd, eStk.size()) ans.push_back(eStk[i] ^ 1);
      |     ^~~
islands.cpp:20:9: warning: 'sInd' may be used uninitialized in this function [-Wmaybe-uninitialized]
   20 |     int sInd;
      |         ^~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 21
• Subtask 4: 8.399999999999999 / 24
• Subtask 5: 0 / 45