Submission #885303

#	Time	Username	Problem	Language	Result	Execution time	Memory
885303		mgl_diamond	Arranging Tickets (JOI17_arranging_tickets)	C++17	10 / 100	247 ms	2504 KiB

arranging_tickets

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ii = pair<int, int>;

#define foru(i, l, r) for(int i=(l); i<=(r); ++i)
#define ford(i, l, r) for(int i=(l); i>=(r); --i)
#define fore(x, v) for(auto &x : v)
#define all(x) (x).begin(), (x).end()
#define sz(x) (int)(x).size()
#define fi first
#define se second
#define file "input"

template<class T> bool minimize(T &a, T b) { if (a > b) { a = b; return 1; } return 0; }
template<class T> bool maximize(T &a, T b) { if (a < b) { a = b; return 1; } return 0; }

void setIO() {
  ios::sync_with_stdio(0);
  cin.tie(0); cout.tie(0);
  if (fopen(file".inp", "r")) {
    freopen(file".inp", "r", stdin);
    freopen(file".out", "w", stdout);
  }
}

const int N = 2e5+5;
int n, m, a[N], b[N], c[N];

int cnt[N];
int mx;

void inc(int l, int r, bool t, int val) {
  if (l > r) swap(l, r);
  if (!t) foru(i, l, r-1) cnt[i] += val;
  else {
    foru(i, 1, l-1) cnt[i] += val;
    foru(i, r, n) cnt[i] += val;
  }
}

void solve1() {
	int mn = N;
	for(int mask=0; mask<(1<<m); ++mask) {
    foru(i, 1, n) cnt[i] = 0;
    mx = 0;
    foru(i, 1, m)
      if (mask >> (i-1) & 1) {
        inc(a[i], b[i], 0, 1);
      }
      else {
        inc(a[i], b[i], 1, 1);
      }
    foru(i, 1, n) maximize(mx, cnt[i]);
//    if (mx == 2) {
//      foru(i, 1, n) cout << cnt[i] << " ";
//      cout << "\n";
//    }
    minimize(mn, mx);
	}
	cout << mn;
}

void solve2() {
  foru(i, 1, n) cnt[i] = 0;
  foru(j, 1, m) inc(a[j], b[j], 0, 1);
  vector<int> dir(n+1, 0);
  while (true) {
    bool opt = 1;
    foru(i, 1, m) {
      int lst = *max_element(cnt+1, cnt+n+1);
      inc(a[i], b[i], dir[i], -1);
      inc(a[i], b[i], dir[i]^1, 1);
      int cur = *max_element(cnt+1, cnt+n+1);
      if (cur < lst) {
        dir[i] ^= 1;
        opt = 0;
        break;
      } else {
        inc(a[i], b[i], dir[i]^1, -1);
        inc(a[i], b[i], dir[i], 1);
      }
    }
    if (opt) break;
  }
  cout << *max_element(cnt+1, cnt+n+1);
}

int main() {
	setIO();

	cin >> n >> m;
	foru(i, 1, m) {
		cin >> a[i] >> b[i] >> c[i];
	}
	foru(i, 1, m) {
    while (c[i]-->1) {
      ++m;
      a[m] = a[i];
      b[m] = b[i];
    }
	}

//  solve1(); cout << "\n";
//  solve2();
	if (n <= 20 && m <= 20) solve1();
	else solve2();
}

Compilation message (stderr)

arranging_tickets.cpp: In function 'void setIO()':
arranging_tickets.cpp:22:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |     freopen(file".inp", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
arranging_tickets.cpp:23:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |     freopen(file".out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 35
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 15