Submission #985719

#	Time	Username	Problem	Language	Result	Execution time	Memory
985719		yoav_s	Swapping Cities (APIO20_swap)	C++17	17 / 100	2045 ms	22732 KiB

swap

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

typedef int ll;
typedef pair<ll,ll> p;
typedef pair<ll, p> tri;
typedef vector<ll> v;
typedef vector<v> vv;
typedef vector<p> vp;
typedef vector<tri> vtri;
typedef vector<vtri> vvtri;
typedef vector<vvtri> vvvtri;
typedef vector<vv> vvv;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<vvb> vvvb;
typedef vector<p> vp;
typedef vector<vp> vvp;
typedef vector<vvp> vvvp;
typedef vector<vvvp> vvvvp;
#define double long double
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<vvd> vvvd;

const ll mod = 1e9 + 7;
const ll INF = 1e18;

#define f first
#define s second
#define pb push_back
#define eb emplace_back
#define loop(a) for (ll i = 0; i < a; i++)
#define setmin(a, b) a = min(a, b)
#define setmax(a, b) a = max(a, b)
#define all(v) v.begin(), v.end()

#include "swap.h"
ll res = -1;
vvp graph;
ll maxW = -INF;
ll N;
v weightInflate;

ll getParent(ll i, v &dsuPar, v &times, ll time)
{
  if (times[i] > time) return i;
  return getParent(dsuPar[i], dsuPar, times, time);
}
v dsuParent, timeBecomeNotRoot, dsuSize, timeValid;
void init(int Nn, int M, std::vector<int> U, std::vector<int> V, std::vector<int> W) {
  N = Nn;
  for (auto x : W) weightInflate.pb(x);
  sort(all(weightInflate));
  weightInflate.erase(unique(all(weightInflate)), weightInflate.end());
  map<ll, ll> weightShrink;
  for (ll i = 0; i < weightInflate.size(); i++) weightShrink[weightInflate[i]] = i;
  maxW = weightInflate.size() - 1;
  graph = vvp(N);
  for (ll i = 0; i < M; i++)
  {
    graph[U[i]].eb(V[i], weightShrink[W[i]]);
    graph[V[i]].eb(U[i], weightShrink[W[i]]);
  }
  dsuParent = v(N);
  timeBecomeNotRoot = v(N, INF);
  dsuSize = v(N, 1);
  timeValid = v(N, INF);
  for (ll i = 0; i < N; i++) dsuParent[i] = i;
  vtri edgesByW;
  for (ll i = 0; i < M; i++) edgesByW.eb(weightShrink[W[i]], p(U[i], V[i]));
  sort(all(edgesByW));
  v curDegree(N, 0);
  for (auto x : edgesByW)
  {
    ll l = x.s.f, r = x.s.s;
    ll p1 = getParent(l, dsuParent, timeBecomeNotRoot, x.f), p2 = getParent(r, dsuParent, timeBecomeNotRoot, x.f);
    if (p1 == p2)
    {
      timeValid[p1] = min(timeValid[p1], x.f);
      continue;
    }
    if (dsuSize[p1] < dsuSize[p2]) swap(p1, p2);
    dsuParent[p1] = p2;
    dsuSize[p2] += dsuSize[p1];
    timeBecomeNotRoot[p1] = x.f;
    curDegree[l]++; curDegree[r]++;
    if ((timeValid[p1] < INF || curDegree[l] >= 3 || curDegree[r] >= 3) && timeValid[p2] == INF) timeValid[p2] = x.f;
  }
}

int getMinimumFuelCapacity(int X, int Y) {
  ll mini = 0, maxi = maxW + 1;
  while (mini < maxi)
  {
    ll mid = (mini + maxi) / 2;
    ll p1 = getParent(X, dsuParent, timeBecomeNotRoot, mid), p2 = getParent(Y, dsuParent, timeBecomeNotRoot, mid);
    bool poss = (p1 == p2 && timeValid[p1] <= mid);
    if (poss)
    {
      maxi = mid;
    }
    else
    {
      mini = mid + 1;
    }
  }
  if (mini > maxW) return -1;
  return weightInflate[mini];
}
/*
int main() {
  int N, M;
  assert(2 == scanf("%d %d", &N, &M));
  
  std::vector<int> U(M), V(M), W(M);
  for (int i = 0; i < M; ++i) {
    assert(3 == scanf("%d %d %d", &U[i], &V[i], &W[i]));
  }

  int Q;
  assert(1 == scanf("%d", &Q));

  std::vector<int> X(Q), Y(Q);
  for (int i = 0; i < Q; ++i) {
    assert(2 == scanf("%d %d", &X[i], &Y[i]));
  }

  init(N, M, U, V, W);
  
  std::vector<int> minimum_fuel_capacities(Q);
  for (int i = 0; i < Q; ++i) {
    minimum_fuel_capacities[i] = getMinimumFuelCapacity(X[i], Y[i]);
  }

  for (int i = 0; i < Q; ++i) {
    printf("%d\n", minimum_fuel_capacities[i]);
  }
  
  return 0;
}
/**/

Compilation message (stderr)

swap.cpp:142:1: warning: "/*" within comment [-Wcomment]
  142 | /**/
      |  
swap.cpp:27:16: warning: overflow in conversion from 'double' to 'll' {aka 'int'} changes value from '1.0e+18' to '2147483647' [-Woverflow]
   27 | const ll INF = 1e18;
      |                ^~~~
swap.cpp: In function 'void init(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
swap.cpp:57:20: warning: comparison of integer expressions of different signedness: 'll' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |   for (ll i = 0; i < weightInflate.size(); i++) weightShrink[weightInflate[i]] = i;
      |                  ~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 7
• Subtask 3: 17 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27