Submission #396256

#	Time	Username	Problem	Language	Result	Execution time	Memory
396256		MarcoMeijer	Teleporters (IOI08_teleporters)	C++14	100 / 100	997 ms	46904 KiB

teleporters

#include <bits/stdc++.h>
using namespace std;
 
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e18
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
 
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
 
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const vector<T>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class T> void OUT(const vector<T>& x) {RE(i,x.size()) OUT(i==0?"":" ",x[i]);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
 
// dp
template<class T> bool ckmin(T&a, T&b) { bool bl = a > b; a = min(a,b); return bl;}
template<class T> bool ckmax(T&a, T&b) { bool bl = a < b; a = max(a,b); return bl;}
 
void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}
 
 
//===================//
//   begin program   //
//===================//
 
const int MX = 2e6+10;
const int N = (1<<20);

int n, m;
int w[MX], e[MX];
vi dif;
int f[MX];
bitset<MX> used;

int getCycleLength(int u) {
    if(used[u]) return 0;
    used[u] = 1;
    return 1 + getCycleLength(f[u]);
}

const int SQ = 0x10000;
int cnt[SQ];

void radixSort(vi& v) {
    vi nv = v;

    RE(i,SQ) cnt[i]=0;
    FOR(i,v) cnt[i&0xFFFF]++;
    REP(i,1,SQ) cnt[i] += cnt[i-1];
    REV(i,0,v.size()) nv[--cnt[v[i]&0xFFFF]] = v[i];
    v = nv;

    RE(i,SQ) cnt[i]=0;
    FOR(i,v) cnt[(i>>16)&0xFFFF]++;
    REP(i,1,SQ) cnt[i] += cnt[i-1];
    REV(i,0,v.size()) nv[--cnt[(v[i]>>16)&0xFFFF]] = v[i];
    v = nv;
}

void program() {
    IN(n,m);
    RE(i,n) IN(w[i],e[i]);

    // coördinate compression
    RE(i,n) dif.pb(w[i]), dif.pb(e[i]);
    radixSort(dif);
    RE(i,n) w[i] = lower_bound(all(dif), w[i]) - dif.begin();
    RE(i,n) e[i] = lower_bound(all(dif), e[i]) - dif.begin();

    // create function
    RE(i,n) f[w[i]] = e[i]+1;
    RE(i,n) f[e[i]] = w[i]+1;

    // find initial ans
    int ans = 0;
    int x = 0;
    while(x != dif.size()) {
        ans++;
        used[x] = 1;
        x = f[x];
    }

    // find cycles
    vi difCycles;
    RE(i,dif.size()) {
        if(used[i]) continue;
        difCycles.pb(getCycleLength(i));
    }
    radixSort(difCycles);

    // create new edges
    RE(_,m) {
        if(difCycles.empty()) {
            difCycles.pb(1);
            ans += 1;
        } else {
            ans += difCycles.back(); difCycles.pop_back();
            ans += 2;
        }
    }

    OUTL(ans);
}

Compilation message (stderr)

teleporters.cpp: In function 'void program()':
teleporters.cpp:113:13: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  113 |     while(x != dif.size()) {
      |           ~~^~~~~~~~~~~~~

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