Submission #124657

#	Time	Username	Problem	Language	Result	Execution time	Memory
124657		Benq	Bridges (APIO19_bridges)	C++14	100 / 100	2170 ms	12324 KiB

bridges

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)

#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound

#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rsz resize

const int MOD = 1000000007; // 998244353
const ll INF = 1e18;
const int MX = 200005;
const ld PI = 4*atan((ld)1);

template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }

namespace input {
    template<class T> void re(complex<T>& x);
    template<class T1, class T2> void re(pair<T1,T2>& p);
    template<class T> void re(vector<T>& a);
    template<class T, size_t SZ> void re(array<T,SZ>& a);

    template<class T> void re(T& x) { cin >> x; }
    void re(double& x) { string t; re(t); x = stod(t); }
    void re(ld& x) { string t; re(t); x = stold(t); }
    template<class Arg, class... Args> void re(Arg& first, Args&... rest) { 
        re(first); re(rest...); 
    }

    template<class T> void re(complex<T>& x) { T a,b; re(a,b); x = cd(a,b); }
    template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.f,p.s); }
    template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
    template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
}

using namespace input;

namespace output {
    template<class T1, class T2> void pr(const pair<T1,T2>& x);
    template<class T, size_t SZ> void pr(const array<T,SZ>& x);
    template<class T> void pr(const vector<T>& x);
    template<class T> void pr(const set<T>& x);
    template<class T1, class T2> void pr(const map<T1,T2>& x);

    template<class T> void pr(const T& x) { cout << x; }
    template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) { 
        pr(first); pr(rest...); 
    }

    template<class T1, class T2> void pr(const pair<T1,T2>& x) { 
        pr("{",x.f,", ",x.s,"}"); 
    }
    template<class T> void prContain(const T& x) {
        pr("{");
        bool fst = 1; for (const auto& a: x) pr(!fst?", ":"",a), fst = 0; // const needed for vector<bool>
        pr("}");
    }
    template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
    template<class T> void pr(const vector<T>& x) { prContain(x); }
    template<class T> void pr(const set<T>& x) { prContain(x); }
    template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
    
    void ps() { pr("\n"); }
    template<class Arg> void ps(const Arg& first) { 
        pr(first); ps(); // no space at end of line
    }
    template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) { 
        pr(first," "); ps(rest...); // print w/ spaces
    }
}

using namespace output;

namespace io {
    void setIn(string s) { freopen(s.c_str(),"r",stdin); }
    void setOut(string s) { freopen(s.c_str(),"w",stdout); }
    void setIO(string s = "") {
        ios_base::sync_with_stdio(0); cin.tie(0); // fast I/O
        if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
    }
}

using namespace io;

template<class T> T invGeneral(T a, T b) {
    a %= b; if (a == 0) return b == 1 ? 0 : -1;
    T x = invGeneral(b,a); 
    return x == -1 ? -1 : ((1-(ll)b*x)/a+b)%b;
}

template<class T> struct modular {
    T val; 
    explicit operator T() const { return val; }
    modular() { val = 0; }
    template<class U> modular(const U& v) {
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD;
    }
    friend ostream& operator<<(ostream& os, const modular& a) { return os << a.val; }
    friend bool operator==(const modular& a, const modular& b) { return a.val == b.val; }
    friend bool operator!=(const modular& a, const modular& b) { return !(a == b); }

    modular operator-() const { return modular(-val); }
    modular& operator+=(const modular& m) { if ((val += m.val) >= MOD) val -= MOD; return *this; }
    modular& operator-=(const modular& m) { if ((val -= m.val) < 0) val += MOD; return *this; }
    modular& operator*=(const modular& m) { val = (ll)val*m.val%MOD; return *this; }
    friend modular exp(modular a, ll p) {
        modular ans = 1; for (; p; p /= 2, a *= a) if (p&1) ans *= a;
        return ans;
    }
    friend modular inv(const modular& a) { 
        auto i = invGeneral(a.val,MOD); assert(i != -1);
        return i;
    } // equivalent to return exp(b,MOD-2) if MOD is prime
    modular& operator/=(const modular& m) { return (*this) *= inv(m); }
    
    friend modular operator+(modular a, const modular& b) { return a += b; }
    friend modular operator-(modular a, const modular& b) { return a -= b; }
    friend modular operator*(modular a, const modular& b) { return a *= b; }
    
    friend modular operator/(modular a, const modular& b) { return a /= b; }
};

typedef modular<int> mi;
typedef pair<mi,mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;

const int BLOCK = 500;

struct DSU {
    int sz[50001], par[50001];
    void init() {
        FOR(i,1,50001) sz[i] = 1, par[i] = i;
    }
    int get(int x) {
        return par[x]==x?x:par[x]=get(par[x]);
    }
    void unite(int a, int b) {
        a = get(a), b = get(b);
        if (a == b) return;
        if (sz[a] < sz[b]) swap(a,b);
        par[b] = a; sz[a] += sz[b];
    }
};

DSU D;
int n,m,q,w[100000],st[100000];
pi ed[100000];
vi adj[50001];
vector<array<int,4>> ev;
vector<array<int,3>> query;
vi del;
int vis[50001],ans[100000];

void process(int x) {
    D.unite(ed[x].f,ed[x].s);
}

void addEdge(int x) {
    int a = D.get(ed[x].f), b = D.get(ed[x].s);
    adj[a].pb(b), adj[b].pb(a); del.pb(a), del.pb(b);
}

int tmp, tot;

void dfs(int x) {
    vis[x] = tmp; tot += D.sz[x];
    trav(t,adj[x]) if (vis[t] != tmp) dfs(t);
}

void solve(int lo, int hi) {
    D.init();
    vector<array<int,3>> qt, bad;
    while (sz(query) && query.back()[1] <= hi) {
        qt.pb(query.back()); query.pop_back();
    }
    // ps(ev); 
    sort(all(qt));
    int ind = 0;
    while (sz(qt)) {
        int w = qt.back()[0], i = qt.back()[1], s = qt.back()[2]; qt.pop_back();
        for (;ind < sz(ev) && ev[ind][0] >= w; ind++) {
            if (hi < ev[ind][2] || ev[ind][3] < lo) continue;
            if (ev[ind][2] <= lo && hi <= ev[ind][3]) process(ev[ind][1]);
            else bad.pb({ev[ind][1],ev[ind][2],ev[ind][3]});
        }
        trav(z,bad) if (z[1] <= i && i <= z[2]) addEdge(z[0]);
        tmp ++; tot = 0;
        dfs(D.get(s)); ans[i] = tot;
        trav(t,del) adj[t].clear();
        del.clear();
    }
}

int main() {
    setIO(); re(n,m);
    F0R(i,m) re(ed[i],w[i]);
    re(q);
    F0R(i,q) {
        ans[i] = -1;
        int t; re(t);
        if (t == 1) {
            int b,r; re(b,r); b--;
            ev.pb({w[b],b,st[b],i}); 
            w[b] = r; st[b] = i+1;
        } else {
            int s,w; re(s,w);
            query.pb({w,i,s});
        }
    }
    F0R(b,m) ev.pb({w[b],b,st[b],q-1}); 
    sort(all(ev)); reverse(all(ev)); reverse(all(query));
    for (int lo = 0; lo < q; lo += BLOCK) solve(lo,min(lo+BLOCK,q)-1);
    F0R(i,q) if (ans[i] != -1) ps(ans[i]);
}


/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?), set tle
    * do smth instead of nothing and stay organized
*/

Compilation message (stderr)

bridges.cpp: In function 'void io::setIn(std::__cxx11::string)':
bridges.cpp:113:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
bridges.cpp: In function 'void io::setOut(std::__cxx11::string)':
bridges.cpp:114:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 27 / 27