Submission #425027

#	Time	Username	Problem	Language	Result	Execution time	Memory
425027		ollel	Boxes with souvenirs (IOI15_boxes)	C++14	20 / 100	1 ms	332 KiB

boxes

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

#define rep(i,a,b) for(int i = a; i < b; i++)
#define pb push_back
#define lso(x) x&(-x)

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;

int n, k, l;
vi p;
vi pos;

ll min(ll a, int b) {return min(a, (ll)b);}

ll kone() {
  ll ans = 0;
  rep(i,0,n) {
    ans += 2*min(pos[i], l - pos[i]);
  }
  return ans;
}

ll kn() {
  ll ans = l;
  ans = min(ans, 2*(l - pos[0]));
  ans = min(ans, 2*pos[n - 1]);
  rep(i,0,n - 1) {
    ans = min(ans, 2*pos[i] + 2*(l - pos[i + 1]));
  }
  return ans;
}

ll ev(int ss) {
  ll ans = 0;
  int fhc = l / 2;
  int shc = l / 2 + (l & 1);
  int a = 0, b = 0;
  while (a < n) {
    if (ss&(1<<a)) while (ss&(1<<b) && b < n) {b++;}
    else while (!(ss&(1<<b)) && b < n) {b++;}
    b--;
    if (pos[b] - pos[a] > k) return 1e18;
    if (pos[b] <= fhc) ans += 2*pos[b];
    else if (pos[a] >= shc) ans += 2*(l - pos[a]);
    else {
      int low = a, high = b + 1, c;
      while (high - low > 1) {
        c = (high + low) / 2;
        if (pos[c] >= shc) high = c;
        else low = c;
      }
      ll cand1 = n, cand2 = 2*pos[c] + 2*(l - pos[c + 1]);
      ans += min(cand1, cand2);
    }
    a = b = b + 1;
  }
  return ans;
}

ll n10() {
  ll ans = 1e18;
  rep(ss, 0, pow(2, n-1)) ans = min(ans, ev(ss));
  return ans;
}

ll delivery(int N, int K, int L, int positions[]) {
  n = N; k = K; l = L;
  pos.resize(n); rep(i,0,n) pos[i] = positions[i];
  if (k == 1) return kone();
  else if (k == n) return kn();
  else if (n <= 10) return n10();
  return 0;
}


// int main() {
//   int a = 3, b = 2, c = 8;
//   int pp[3] = {1, 2, 5};
//   cout << delivery(a, b, c, pp);
// }

Compilation message (stderr)

boxes.cpp: In function 'll ev(int)':
boxes.cpp:57:36: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   57 |       ll cand1 = n, cand2 = 2*pos[c] + 2*(l - pos[c + 1]);
      |                                    ^

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 30