Submission #532843

#	Time	Username	Problem	Language	Result	Execution time	Memory
532843		ohohorz	Swapping Cities (APIO20_swap)	C++14	37 / 100	2050 ms	25964 KiB

swap

#include "swap.h"

#include <vector>
#include<set>
#include<algorithm>
#include<climits>
using namespace std;

// #define int long long
#define pb push_back
#define mp make_pair
#define pii pair<int,int>
#define sz(x) (int)x.size()

const int MAXN = 1e5 + 5;
const int INF = INT_MAX;

int n, m;
// vector< pair <int,int> > g[MAXN];
vector< pair<pii,int> > ed;
vector<int> wts;
int deg[MAXN];
int tot, onedeg, twodeg;
bool vis[MAXN];
vector<pii> g[MAXN];
void dfs(int u){
  vis[u] = 1;
  tot ++;
  onedeg += (deg[u] == 1);
  twodeg += (deg[u] == 2);
  for(auto p:g[u]){
    if(!vis[p.first]) 
      dfs(p.first);
  }
} 

bool cmp(pair<pii,int> a, pair<pii,int> b){
  if(a.second < b.second) return 1;
  if(a.second > b.second) return 0;
  return 1;
}

void init(int N, int M, std::vector<int> U, std::vector<int> V, std::vector<int> W) {
  n = N,m = M;
  set<int> wt;
  for(int i = 0;i < m;i++){
    int u = U[i] + 1;
    int v = V[i] + 1;
    ed.pb(mp(mp(u, v), W[i]));
    wt.insert(W[i]);
  }
  sort(ed.begin(), ed.end(), cmp);
  for(int gg:wt) wts.pb(gg);
}

int getMinimumFuelCapacity(int X, int Y) {
  X++, Y++;
  int l = 0, r = sz(wts) - 1;
  int ans = INF;

  while(l <= r){
    int md = (l + r) >> 1LL;
    int W = wts[md];
    
    
    for(int i =1;i<=n;i++) g[i].clear(), vis[i] = 0;
    for(int i =1;i<=n;i++) deg[i] = 0;
    for(int i = 0;i<m;i++){
      if(ed[i].second > W) break;
      int u = ed[i].first.first;
      int v = ed[i].first.second;
      int w = ed[i].second;  
      g[u].pb(mp(v, w));
      g[v].pb(mp(u, w));
      deg[u] ++;
      deg[v] ++;
    }
    tot = 0, onedeg = 0, twodeg=0;
    bool ok = 1;
    dfs(X);
    ok &= vis[Y];

    if(!ok){
      l = md + 1;
      continue;
    }
    // connected hai x and y
    if(tot == (onedeg + twodeg) and onedeg == 2 and twodeg == (tot - 2)) ok = 0;
    if(ok==1){
      ans = min(ans, W);
      r = md - 1;
    }else l = md + 1;
  }
  if(ans == INF) return -1;
  return ans;
}

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