Submission #1057470

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057470		dosts	Swapping Cities (APIO20_swap)	C++17	100 / 100	218 ms	28636 KiB

swap

#include "swap.h"
#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
using namespace std;
//#define int long long
#define pii pair<int,int>
#define ff first
#define ss second
#define sp << " " <<    
#define all(cont) cont.begin(),cont.end()
#define vi vector<int>
const int MOD = 1e9+7,inf = 2e9;
const int L = 2e5+1;
vi getter(L,inf);
struct DSU {
  int n;
  vi dad,change,sz;
  DSU(){};
  DSU(int nn) {
    n = nn;
    dad.resize(n),change.assign(n,inf),sz.assign(n,1);
    iota(dad.begin(),dad.end(),0ll);
  }
  int find(int x,int t) {
    if (change[x]==inf || change[x] > t) return x;
    return find(dad[x],t);
  }
  void unite(int x,int y,int t) {
    int a = find(x,t);
    int b = find(y,t);
    if (a == b) {
      getter[a] = min(getter[a],t);
      return;
    }
    if (sz[a] < sz[b]) swap(a,b);
    dad[b] = a;
    sz[a]+=sz[b];
    change[b] = t;
    if (getter[b] != inf) getter[a] = min(getter[a],t);
  }
};

vi vv;

int idx(int xx) {
  return upper_bound(all(vv),xx)-vv.begin();
}

map<int,int> realy;
DSU dsu;

int nn;
void init(int N, int M,
          std::vector<int> U, std::vector<int> V, std::vector<int> W) {
    nn = N;
    for (int i=0;i<M;i++) vv.push_back(W[i]);
    sort(all(vv));
    vv.erase(unique(all(vv)),vv.end());
    int cc = 1;
    for (auto it : vv) realy[cc++] = it; 
    dsu = DSU(N);
    vector<pair<int,pii>> edges;
    for (int i=0;i<M;i++) edges.push_back({idx(W[i]),{U[i],V[i]}});
    vi edg(N,0);
    sort(all(edges));
    for (auto it : edges) {
      dsu.unite(it.ss.ff,it.ss.ss,it.ff);
      edg[it.ss.ff]++;
      edg[it.ss.ss]++;
      if (edg[it.ss.ff] == 3 || edg[it.ss.ss] == 3) {
        getter[dsu.find(it.ss.ff,it.ff)] = min(it.ff,getter[dsu.find(it.ss.ff,it.ff)]);
      }
    }
}

int getMinimumFuelCapacity(int X, int Y) {
  int sz = vv.size();
  int l = 1;
  int r = sz;
  while (l<=r) {
    int m = (l+r) >> 1;
    if (dsu.find(X,m) != dsu.find(Y,m)) {
      l = m+1;
      continue;
    }
    int p = dsu.find(X,m);
    if (getter[p] > m) l = m+1;
    else r = m-1;
  }
  if (l <= sz) return realy[l];
  return -1;
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 20 / 20
• Subtask 5: 23 / 23
• Subtask 6: 27 / 27