제출 #1348110

#제출 시각아이디문제언어결과실행 시간메모리
1348110tamir1Alternating Heights (CCO22_day1problem1)C++20
25 / 25
112 ms4588 KiB
#include <bits/stdc++.h>
using namespace std;


#define int long long
#define ff first
#define ss second
#define sz(a) (int)(a).size()
#define all(a) (a).begin(),(a).end()
#define pb push_back



bool dfs(int v, vector<vector<int>> &adj, vector<int> &vis) {
    vis[v] = 1; // in recursion stack

    for (int u : adj[v]) {
        if (vis[u] == 0) {
            if (dfs(u, adj, vis)) return true;
        } else if (vis[u] == 1) {
            return true; 
        }
    }

    vis[v] = 2; 
    return false;
}

bool hasCycle(int n, vector<vector<int>> &adj) {
    vector<int> vis(n + 1, 0);

    for (int i = 1; i <= n; i++) {
        if (vis[i] == 0) {
            if (dfs(i, adj, vis)) return true;
        }
    }
    return false;
}



signed main() {
    ios_base::sync_with_stdio(0);cin.tie(0);

    
    int n, k, q;
    cin >> n >> k >> q;
    vector<int> dp(n + 1), a(n + 1);
    vector<vector<int>> adj;
    adj.assign(n + 1, {});
    for(int i = 1; i <= n; i++) cin >> a[i];
    dp[0] = 0;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) adj[j].clear();
        int j = max(i, dp[i - 1]);
        dp[i] = j;
        for(int k = i + 1; k <= j; k++) {
            if(k & 1) adj[a[k - 1]].pb(a[k]);
            else adj[a[k]].pb(a[k - 1]);
        }
        j++;
        for(; j <= n; j++) {
            if(j & 1) adj[a[j - 1]].pb(a[j]);
            else adj[a[j]].pb(a[j - 1]);
            // cout << i << " " << j << "\n";
            if(!hasCycle(k, adj)) dp[i] = j;
            else break;
        }
        // cout << dp[i] << " ";
    }

    for(int i = 1; i <= q; i++) {
        int x, y;
        cin >> x >> y;
        cout << (dp[x] >= y ? "YES\n" : "NO\n");
    }

}
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