Submission #1274851

#	Time	Username	Problem	Language	Result	Execution time	Memory
1274851		icebear	Joker (BOI20_joker)	C++20	14 / 100	2093 ms	3700 KiB

Joker

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

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebear"

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int numNode, numEdge, numQuery;
ii edge[N];

struct DisjointSet {
    vector<int> lab;
    DisjointSet(int n = 0): lab(n + 5, -1) {}

    int root(int v) {
        return (lab[v] < 0 ? v : lab[v] = root(lab[v]));
    }

    bool unite(int u, int v) {
        u = root(u);
        v = root(v);
        if (u == v) return false;
        if (lab[u] > lab[v]) swap(u, v);
        lab[u] += lab[v];
        lab[v] = u;
        return true;
    }
} dsu;

void init(void) {
    cin >> numNode >> numEdge >> numQuery;
    FOR(i, 1, numEdge) cin >> edge[i].fi >> edge[i].se;
}

void process(void) {
    while(numQuery--) {
        int l, r;
        cin >> l >> r;
        dsu = DisjointSet(2 * numNode);
        FOR(i, 1, l - 1) {
            dsu.unite(edge[i].fi, edge[i].se + numNode);
            dsu.unite(edge[i].se, edge[i].fi + numNode);
        }

        FOR(i, r + 1, numEdge) {
            dsu.unite(edge[i].fi, edge[i].se + numNode);
            dsu.unite(edge[i].se, edge[i].fi + numNode);
        }

        bool biparite = true;
        FOR(i, 1, numNode) if (dsu.root(i) == dsu.root(i + numNode)) {
            biparite = false;
            break;
        }
        cout << (biparite == false ? "YES\n" : "NO\n");
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:94:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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