Submission #800837

#	Time	Username	Problem	Language	Result	Execution time	Memory
800837		TB_	Joker (BOI20_joker)	C++17	100 / 100	220 ms	27964 KiB

Joker

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

// #undef _GLIBCXX_DEBUG                // disable run-time bound checking, etc
// #pragma GCC optimize("Ofast,inline") // Ofast = O3,fast-math,allow-store-data-races,no-protect-parens
// #pragma GCC optimize ("unroll-loops")

// #pragma GCC target("bmi,bmi2,lzcnt,popcnt")                      // bit manipulation
// #pragma GCC target("movbe")                                      // byte swap
// #pragma GCC target("aes,pclmul,rdrnd")                           // encryption
// #pragma GCC target("avx,avx2,f16c,fma,sse3,ssse3,sse4.1,sse4.2") // SIMD

// #include <bits/extc++.h>
// using namespace __gnu_pbds;
// template<class T>using ordered_set = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
// template<class T>using ordered_multiset = tree<T, null_type, less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define ll long long
#define INF (ll)1e9+7
#define fo(i, n) for(int i=0;i<((ll)n);i++)
#define deb(x) cout << #x << " = " << x << endl;
#define deb2(x, y) cout << #x << " = " << x << ", " << #y << " = " << y << endl
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define LSOne(S) ((S) & (-S))
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
inline int readint(){ int v = 0; char c; while((c = getchar()) != EOF && c != ' ' && c != '\n'){ v *= 10; v += c - '0'; } return v; }
inline int readintsigned() { int v = 0; int sign = 1; char c = getchar(); if (c == '-') { sign = -1; } else { v += c - '0'; } while ((c = getchar()) != EOF && c != ' ' && c != '\n') { v *= 10; v += c - '0'; } return v * sign; }
inline string readstring() { string s; char c; while ((c = getchar()) != EOF && c != '\n' && c != ' ') { s.push_back(c); } return s; }
template <class result_t=std::chrono::milliseconds,class clock_t=std::chrono::steady_clock,class duration_t = std::chrono::milliseconds>
auto since(std::chrono::time_point<clock_t, duration_t> const& start){return std::chrono::duration_cast<result_t>(clock_t::now() - start);}
typedef pair<int, int> pii;
typedef pair<ll, ll> pl;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpii;
typedef vector<pl> vpl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef vector<vpii> vvpii;
typedef vector<vpl> vvpl;



struct UnionFind{
    vl degree, height, p, siz, extraHeight;
    vector<pair<pii, pii>> updates; // pUpdates, sizUpdate
    vi possibleUpdate, extraHeightUpdate;
    int n;
    int possible = 0;
    UnionFind(int n) : n(n) {
        height.assign(n, 0);
        extraHeight.assign(n, 0);
        degree.assign(n, 0); 
        p.assign(n, 0); 
        siz.assign(n, 1); 
        fo(i, n) p[i] = i;
    }

    int find(int x){
        if(x == p[x]) return x;
        int res = find(p[x]);
        height[x] = height[p[x]]+1+extraHeight[x];
        return res;
    }


    void unite(int a, int b){
        possibleUpdate.pb(possible);
        extraHeightUpdate.pb(-1);
        updates.pb({{-1, -1}, {-1, -1}});
        int a2 = find(a);
        int b2 = find(b);
        if(a2==b2){
            if(height[a]%2 == height[b]%2) possible++;
        }else{
            if(siz[b2] > siz[a2]) {
                swap(a2, b2);
                swap(a, b);
            }
            updates[updates.size()-1] = {{b2, p[b2]}, {a2, siz[a2]}};
            siz[a2] += siz[b2];
            p[b2] = a2;
            if((height[b2]%2 == height[b]%2)^(height[a2]%2 == height[a]%2)){
                extraHeight[b2]++;
                extraHeightUpdate[extraHeightUpdate.size()-1] = b2;
            }
        }
    }  


    void rollback(){
        possible = possibleUpdate[possibleUpdate.size()-1];
        int heightupdate = extraHeightUpdate[extraHeightUpdate.size()-1];
        if(heightupdate != -1) extraHeight[heightupdate]--;
        pair<pl, pl> up = updates[updates.size()-1];
        if(up.F.F != -1){
            p[up.F.F] = up.F.S;
            siz[up.S.F] = up.S.S;

        }
        updates.pop_back();
        possibleUpdate.pop_back();
        extraHeightUpdate.pop_back();
    }  
};

UnionFind uf(200001);
vpl edges;
vi ans(200001, -1);

void solve(int lo, int hi, int r){
    if(hi < lo) return;

    int mid = (lo + hi) / 2;
    int preSizeLo = uf.updates.size();
    fo(i, mid-lo){
        uf.unite(edges[lo+i].F, edges[lo+i].S);
        if(uf.possible){
            for(int j = mid; j <= hi; j++) ans[j] = r; 
            while(uf.updates.size() != preSizeLo) uf.rollback();
            solve(lo, mid-1, r);
            return;
        }
    }
    int preSizeHi = uf.updates.size();
    for(int i = r; i >= lo; i--){
        if(uf.possible){
            ans[mid] = i;
            break;
        }
        if(i <= lo) continue;
        uf.unite(edges[i].F, edges[i].S);
    }
    while(uf.updates.size() != preSizeHi) uf.rollback();
    uf.unite(edges[mid].F, edges[mid].S);
    solve(mid+1, hi, r);
    while(uf.updates.size() != preSizeLo) uf.rollback();
    for(int i = r; i > max(lo, ans[mid]); i--){
        uf.unite(edges[i].F, edges[i].S);
        if(uf.possible){
            for(int j = lo; j < mid; j++) ans[j] = ans[mid];
            return;
        }
    }
    solve(lo, mid-1, ans[mid]);
}


int main() {
    // cout << fixed << setprecision(20);
    // auto start = std::chrono::steady_clock::now(); // since(start).count()
    cin.tie(0)->sync_with_stdio(0);

    int n, m, q, from, to, que;
    cin >> n >> m >> q;
    fo(i, m){
        cin >> from >> to;
        edges.pb({from-1, to-1});
    }

    solve(0, m-1, m-1);

    fo(x, q){
        cin >> from >> to;
        cout << (ans[from-1]>=to-1?"YES\n":"NO\n");      
    }
    


    exit(0);
}

Compilation message (stderr)

Joker.cpp: In function 'void solve(int, int, int)':
Joker.cpp:124:37: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  124 |             while(uf.updates.size() != preSizeLo) uf.rollback();
      |                   ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
Joker.cpp:138:29: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  138 |     while(uf.updates.size() != preSizeHi) uf.rollback();
      |           ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
Joker.cpp:141:29: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<std::pair<int, int>, std::pair<int, int> > >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  141 |     while(uf.updates.size() != preSizeLo) uf.rollback();
      |           ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~
Joker.cpp: In function 'int main()':
Joker.cpp:158:28: warning: unused variable 'que' [-Wunused-variable]
  158 |     int n, m, q, from, to, que;
      |                            ^~~

• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 25 / 25
• Subtask 4: 10 / 10
• Subtask 5: 22 / 22
• Subtask 6: 29 / 29