Submission #332183

#	Time	Username	Problem	Language	Result	Execution time	Memory
332183		LifeHappen__	Roller Coaster Railroad (IOI16_railroad)	C++14	34 / 100	67 ms	11772 KiB

railroad

#include "railroad.h"
#include <bits/stdc++.h>

using namespace std;

#define ii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define eb emplace_back

struct dsu {
  vector <int> par;
  void init(int n){
    par.assign(n, 0);
    for (int i = 0; i < n; ++i) par[i] = i;
  }
  int findset(int u) {
    if(par[u] == u) return u;
    return par[u] = findset(par[u]);
  }
  bool mergeset(int u, int v) {
    u = findset(u), v = findset(v);
    if(u == v) return false;
    par[v] = u; return true;
  }
} pa;

long long plan_roller_coaster(vector<int> s, vector<int> t) {
  int n = s.size();
  vector <ii> vals;
  int all_mask = 1ll << n;
  int64_t inf = 1e18;
  vector <vector<long long>> dp(all_mask, vector<long long>(n+1, inf));
  for (int i = 0; i < n; ++i) {
    dp[1 << i][i] = 0;
  }
  vector<ii> order_mask;
  for (int i = 2; i < all_mask; ++i) {
    order_mask.eb(__builtin_popcount(i), i);
  }
  sort(begin(order_mask), end(order_mask));
  for (ii &_ : order_mask) {
    int mask = _.se;
    for (int i = 0; i < n; ++i) {
      if(mask >> i & 1) {
        int pre = mask ^ (1ll << i);
        for (int j = 0; j < n; ++j) {
          if(pre >> j & 1) {
            dp[mask][i] = min(dp[mask][i], dp[pre][j] + 1ll * max(0, t[i] - s[j]));
          }
        }
      }
    }
  }
  long long ans = inf;
  for (int i = 0; i < n; ++i) ans = min(ans, dp[all_mask - 1][i]);
  return ans;
}

#ifdef LOCAL
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0); cout.tie(0);

  freopen("in.txt", "r", stdin);

  int n; cin >> n;
  vector <int> s(n), t(n);
  for (int i = 0; i < n; ++i) {
    cin >> s[i] >> t[i];
  }
  cout << plan_roller_coaster(s, t);
}
#endif //LOCAL

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 0 / 30
• Subtask 4: 0 / 36