Submission #389333

#	Time	Username	Problem	Language	Result	Execution time	Memory
389333		VROOM_VARUN	Watching (JOI13_watching)	C++14	50 / 100	1074 ms	4248 KiB

watching

/*
ID: varunra2
LANG: C++
TASK: watching
*/

#include <bits/stdc++.h>
using namespace std;

#ifdef DEBUG
#include "lib/debug.h"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#define debug_arr(...) \
  cerr << "[" << #__VA_ARGS__ << "]:", debug_arr(__VA_ARGS__)
#pragma GCC diagnostic ignored "-Wsign-compare"
//#pragma GCC diagnostic ignored "-Wunused-parameter"
//#pragma GCC diagnostic ignored "-Wunused-variable"
#else
#define debug(...) 42
#endif

#define EPS 1e-9
#define IN(A, B, C) assert(B <= A && A <= C)
#define INF (int)1e9
#define MEM(a, b) memset(a, (b), sizeof(a))
#define MOD 1000000007
#define MP make_pair
#define PB push_back
#define all(cont) cont.begin(), cont.end()
#define rall(cont) cont.end(), cont.begin()
#define x first
#define y second

const double PI = acos(-1.0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> PII;
typedef map<int, int> MPII;
typedef multiset<int> MSETI;
typedef set<int> SETI;
typedef set<string> SETS;
typedef vector<int> VI;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<string> VS;

#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define trav(a, x) for (auto& a : x)
#define sz(x) (int)(x).size()
typedef pair<int, int> pii;
typedef vector<int> vi;
#pragma GCC diagnostic ignored "-Wsign-compare"
// util functions

int n, p, q;
VI vals;

void init() {
  vals.resize(n);
  p = min(p, n);
  q = min(q, n);
}

bool works(int w, bool deb = false) {
  if (p + q >= n) return true;
  VVI dp(p + 1, VI(q + 1, 0));
  for (int i = 0; i <= p; i++) {
    for (int j = 0; j <= q; j++) {
      if (dp[i][j] == n) {
        return true;
      }
      if (i < p) {
        int to = vals[dp[i][j]] + w;
        int ind = lower_bound(all(vals), to) - vals.begin();
        dp[i + 1][j] = max(dp[i + 1][j], ind);
      }
      if (j < q) {
        int to = vals[dp[i][j]] + 2 * w;
        int ind = lower_bound(all(vals), to) - vals.begin();
        dp[i][j + 1] = max(dp[i][j + 1], ind);
      }
    }
  }
  if (deb) trav(x, dp) debug(x);
  return false;
}

int main() {
  // #ifndef ONLINE_JUDGE
  // freopen("watching.in", "r", stdin);
  // freopen("watching.out", "w", stdout);
  // #endif
  cin.sync_with_stdio(0);
  cin.tie(0);

  cin >> n >> p >> q;

  init();

  trav(x, vals) cin >> x;

  sort(all(vals));

  int x = -1;

  for (int b = INF; b >= 1; b /= 2) {
    while (!works(x + b)) x += b;
  }

  cout << max(1, x + 1) << '\n';

  works(x + 1, true);

  return 0;
}

Compilation message (stderr)

watching.cpp: In function 'bool works(int, bool)':
watching.cpp:19:20: warning: statement has no effect [-Wunused-value]
   19 | #define debug(...) 42
      |                    ^~
watching.cpp:84:24: note: in expansion of macro 'debug'
   84 |   if (deb) trav(x, dp) debug(x);
      |                        ^~~~~
watching.cpp:31:11: warning: unused variable 'first' [-Wunused-variable]
   31 | #define x first
      |           ^~~~~
watching.cpp:48:31: note: in definition of macro 'trav'
   48 | #define trav(a, x) for (auto& a : x)
      |                               ^
watching.cpp:84:17: note: in expansion of macro 'x'
   84 |   if (deb) trav(x, dp) debug(x);
      |                 ^

• Subtask 1: 50 / 50
• Subtask 2: 0 / 50