제출 #396565

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
396565		usachevd0	고대 책들 (IOI17_books)	C++14	50 / 100	697 ms	150668 KiB

books

#include <bits/stdc++.h>
#ifndef DEBUG
  #include "books.h"
#endif

using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define all(a) (a).begin(), (a).end()
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
using ld = long double;
template<typename T1, typename T2> bool chkmin(T1 &x, T2 y) {
  return y < x ? (x = y, true) : false; 
}
template<typename T1, typename T2> bool chkmax(T1 &x, T2 y) {
  return y > x ? (x = y, true) : false;
}
void debug_out() {
  cerr << endl;
}
template<typename T1, typename... T2> void debug_out(T1 A, T2... B) {
  cerr << ' ' << A;
  debug_out(B...);
}
template<typename T> void mdebug_out(T* a, int n) {
  for (int i = 0; i < n; ++i) {
    cerr << a[i] << ' ';
  }
  cerr << endl;
}
#ifdef DEBUG
  #define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
  #define mdebug(a, n) cerr << #a << ": ", mdebug_out(a, n)
#else
  #define debug(...) 1337
  #define mdebug(a, n) 1337
#endif
template<typename T> ostream& operator << (ostream& stream, const vector<T> &v) {
  for (auto& x : v) {
    stream << x << ' ';
  }
  return stream;
}
template<typename T1, typename T2> ostream& operator << (ostream& stream, const pair<T1, T2>& p) {
  return stream << p.first << ' ' << p.second;
}


const int INF32 = 1e9;

ll minimum_walk(vector<int> p, int s) {
  int n = p.size();
  ll Ans = 0;
  for (int i = 0; i < n; ++i) Ans += labs(p[i] - i);

  vector<int> cyc(n, -1);
  vector<int> cl(n, +INF32), cr(n, -INF32);
  int C = 0;
  for (int i = 0; i < n; ++i) {
    if (p[i] != i && cyc[i] == -1) {
      int c = C++;
      cl[c] = cr[c] = i;
      int x = i;
      do {
        cyc[x] = c;
        chkmax(cr[c], x);
        x = p[x];
      } while (x != i);
    }
  }
  if (!C) return 0;
  vector<int> G[C];
  vector<int> GR[C];
  for (int c = 0; c < C; ++c) {
    for (int i = cl[c]; i <= cr[c]; ++i) {
      if (cyc[i] != -1 && cyc[i] != c) {
        G[c].push_back(cyc[i]);
        GR[cyc[i]].push_back(c);
      }
    }
  }
  vector<char> used(C, false);
  vector<int> ord;
  function<void(int)> dfs = [&](int v) {
    used[v] = true;
    for (int& u : G[v])
      if (!used[u])
        dfs(u);
    ord.push_back(v);
  };
  for (int c = 0; c < C; ++c)
    if (!used[c])
      dfs(c);
  reverse(all(ord));
  vector<int> scc(C, -1);
  int S = 0;
  function<void(int)> dfs1 = [&](int v) {
    scc[v] = S;
    for (int& u : G[v])
      if (scc[u] == -1)
        dfs1(u);
  };
  for (int& v : ord) {
    if (scc[v] == -1) {
      dfs1(v);
      ++S;
    }
  }
  vector<char> src(S, true);
  for (int c = 0; c < C; ++c) {
    for (int d : G[c]) {
      if (scc[c] != scc[d]) {
        src[scc[d]] = false;
      }
    }
  }
  int min_from_s = +INF32;
  for (int i = 0; i < n; ++i) {
    if (cyc[i] != -1 && src[scc[cyc[i]]]) {
      chkmin(min_from_s, labs(i - s));
    }
  }
  Ans += 2 * min_from_s;
  vector<int> sl(S, +INF32), sr(S, -INF32);
  for (int c = 0; c < C; ++c) {
    int s = scc[c];
    chkmin(sl[s], cl[c]);
    chkmax(sr[s], cr[c]);
  }
  vector<pii> segs;
  for (int s = 0; s < S; ++s) {
    if (src[s]) {
      segs.emplace_back(sl[s], sr[s]);
    }
  }
  sort(all(segs));
  for (int i = 0; i + 1 < segs.size(); ++i) {
    int r1 = segs[i].se;
    int l2 = segs[i + 1].fi;
    assert(r1 < l2);
    Ans += 2 * (l2 - r1);
  }
  return Ans;
}


#ifdef DEBUG
int32_t main() {
#ifdef DEBUG
  freopen("in", "r", stdin);
#endif
  ios::sync_with_stdio(0);
  cin.tie(0);

  int n, s;
  cin >> n >> s;
  vector<int> p(n);
  for (auto& x : p) cin >> x;
  cout << minimum_walk(p, s) << '\n';
    
  return 0;
}
#endif

컴파일 시 표준 에러 (stderr) 메시지

books.cpp: In function 'll minimum_walk(std::vector<int>, int)':
books.cpp:145:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  145 |   for (int i = 0; i + 1 < segs.size(); ++i) {
      |                   ~~~~~~^~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 10 / 10
• Subtask 3: 28 / 28
• Subtask 4: 0 / 20
• Subtask 5: 0 / 30