Submission #719392

#	Time	Username	Problem	Language	Result	Execution time	Memory
719392		Sam_a17	Joker (BOI20_joker)	C++17	25 / 100	94 ms	5440 KiB

Joker

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
#define blt(x) __builtin_popcount(x)
 
#define pb push_back
#define popf pop_front
#define popb pop_back
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(long double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(T v[],V n) {cerr << "["; for(int i = 0; i < n; i++) {print(v[i]); cerr << " "; } cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if (str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }
}
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5 + 10;
int n, m, q, last[N];
int p[N], sz[N], add[N];
int bip;
 
stack<pair<pair<int, int>, pair<int, int>>> st;
 
 
// dsu
void init() {
  bip = 0;
  for(int i = 1; i <= n; i++) {
    p[i] = i, sz[i] = 1;
    add[i] = 0;
  }
}
 
int find(int a) {
  if(a != p[a]) {
    return find(p[a]);
  }
  return p[a];
}
 
int find_sum(int a) {
  if(a != p[a]) {
    return add[a] + find_sum(p[a]);
  }
  return add[a];
}
 
int same(int a, int b) {
  if(find(a) == find(b)) {
    return 1;
  }
  return 0;
}
 
int get_color(int node) {
  int sx = find_sum(node);
  int colx = 1;
  if(sx % 2) colx = 2;
  return colx;
}
 
int merge(int a, int b, int t) {
  if(a == -1) {
    return 0;
  }
 
  int x = a, y = b;
  a = find(a), b = find(b);
 
  if(same(a, b)) {
    int colx = get_color(x), coly = get_color(y);
    int last_bip = bip;
    if(colx == coly) {
      bip = 1;
    }
    return 0;
  }
  
  if(sz[b] > sz[a]) {
    swap(a, b);
  }
 
  int colx = get_color(x), coly = get_color(y);
  // int okk = 0;
  if(colx == coly) {
    add[b]++;
    // okk++;
  }
 
  add[b] -= add[a];
  p[b] = a, sz[a] += sz[b];
  // st.push({{okk, bip}, {a, b}});
  return 1;
}
 
void rollback() {
  if (!st.empty()) {
    auto u = st.top().second;
    int a = u.second, b = u.first;
    sz[a] -= sz[b], p[b] = b;
    add[b] += add[a];
    add[b] -= st.top().first.first;
    bip = st.top().first.second;
    st.pop();
  }
}
 
vector<int> lst;
vector<pair<int, int>> edges;
 
int timer = 0;

bool answ[305][N];

void rec(int l, int r, int L, int R) {
  if(l > r) {
    return;
  }
 
  int mid = (l + r) / 2;
 
  for(int i = l; i < mid; i++) {
    merge(edges[i].first, edges[i].second, timer++);
  }
 
  int opt = R + 1;
  for(int i = R; i >= L && i >= mid; i--) {
    merge(edges[i].first, edges[i].second, timer++);
    if(bip || i == mid) {
      opt = i;
      rollback();
      break;
    }
  }
 
  last[mid] = opt;
  opt = min(opt, R);
 
  for(int i = R; i > opt; i--) {
    rollback();
  }
 
  for(int i = l; i < mid; i++) {
    rollback();
  }
 
  for(int i = R; i > opt; i--) {
    merge(edges[i].first, edges[i].second, timer++);
  }
 
  rec(l, mid - 1, L, opt);
 
  for(int i = R; i > opt; i--) {
    rollback();
  }
 
  for(int i = l; i <= mid; i++) {
    merge(edges[i].first, edges[i].second, timer++);
  }
 
  rec(mid + 1, r, max(opt, mid + 1), R);
 
  for(int i = l; i <= mid; i++) {
    rollback();
  }
}
 
void solve_() {
  cin >> n >> m >> q;
 
  edges.emplace_back(-1, -1);
  for(int i = 1; i <= m; i++) {
    int a, b; cin >> a >> b;
    edges.emplace_back(a, b);
  }
  edges.emplace_back(-1, -1);
 
  // rec(1, m, 1, m);

  for(int j = 1; j <= min(m, 2); j++) {
    init();
    for(int i = 1; i < j; i++) {
      if(!bip) {
        merge(edges[i].first, edges[i].second, timer++);
      }
    }

    answ[j][m + 1] = bip;
    for(int i = m; i >= j; i--) {
      if(!bip) {
        merge(edges[i].first, edges[i].second, timer++);
      }
      answ[j][i] = bip;
    }
  }
 
  //
  for(int i = 1; i <= q; i++) {
    int l, r; cin >> l >> r;

    if(answ[l][r + 1]) {
      cout << "YES" << '\n';
    } else {
      cout << "NO" << '\n';
    }
  }
 
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

Joker.cpp: In function 'int merge(int, int, int)':
Joker.cpp:125:9: warning: unused variable 'last_bip' [-Wunused-variable]
  125 |     int last_bip = bip;
      |         ^~~~~~~~
Joker.cpp: In function 'void setIO(std::string)':
Joker.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 8
• Subtask 3: 25 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29