Submission #571286

#	Time	Username	Problem	Language	Result	Execution time	Memory
571286		Vanilla	Swapping Cities (APIO20_swap)	C++17	13 / 100	408 ms	76744 KiB

swap

#include "swap.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 4e5 + 2;
int extra = 2e5 + 1;
// int extra = 9;
const int lg = 25;
vector <int> ad [maxn];
int deg[maxn];
int dad [maxn];
int val [maxn];
vector <bool> good (maxn, 0);
vector <int> cmp[maxn];
vector <int> depth (maxn);
int dg[maxn];
int up[maxn][lg];
 
void dfs (int u) {
    for (auto v: cmp[u]) {
        depth[v] = depth[u] + 1;
        up[v][0] = u;
        for (int i = 1; i < lg; i++){
            up[v][i] = up[up[v][i-1]][i-1];
        }
        dfs(v);
    }
}
 
int lca (int x, int y) {
    if (depth[x] < depth[y]) {
        swap(x, y);
    }
    int k = depth[x] - depth[y];
    for (int i = 0; i < lg; i++){
        if (k & (1 << i)) {
            x = up[x][i];
        }
    }
    if (x == y) return x;
    for (int i = lg - 1; i >= 0; i--) {
        if (up[x][i] != up[y][i] || !good[up[x][i]]) {
            x = up[x][i];
            y = up[y][i];
        }
    }
    return up[x][0];
}
 
 
int get_dad (int x) {
  return dad[x] = (dad[x] == x ? x: get_dad(dad[x]));
}
 
void find (int u, vector <int> &nodes) {
  nodes.push_back(u);
  for (int v: cmp[u]) {
    find(v, nodes);
  }
}
 
bool propagate (int u) {
  for (int v: ad[u]) {
    good[u]= good[u] | propagate(v);
  }
  return good[u];
}
 
struct edg {
  int x,y,cost;
};
 
bool comp (edg &a, edg &b) {
  return a.cost < b.cost;
}
 
void init(int n, int m, vector<int> u, vector<int> v, vector<int> w) {
  vector <edg> eg;
  good [maxn - 1] = 1;
  for (int i = 0; i < maxn; i++){
    dad[i] = i;
    for (int j = 0; j < lg; j++){
      up[i][j] = maxn - 1;
    }
  }
  for (int i = 0; i < m; i++){
    eg.push_back({u[i], v[i], w[i]});
  }
  sort(eg.begin(), eg.end(), comp);
  for (auto &[u,v,cost]: eg) {
    int p1 = get_dad(u);
    int p2 = get_dad(v);
    deg[u]++;
    deg[v]++;
    val[++extra] = cost;
    dad[p1] = extra;
    dad[p2] = extra;
    cmp[extra].push_back(p1);
    if (p1 != p2) cmp[extra].push_back(p2);
    if (p1 == p2 || deg[u] >= 3 || deg[v] >= 3) {
      good[extra] = 1;
    }
  
  }
  for (int i = maxn - 1; i >= 0; i--){
    if (!cmp[i].empty()) {
      propagate(i);
      dfs(i);
      break;
    }
  }
 
}
 
int getMinimumFuelCapacity(int x, int y) {
  int k = lca(x,y);
  if (!good[k] || k == maxn - 1) return -1;
  return val[k];
}

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