Submission #759306

#	Time	Username	Problem	Language	Result	Execution time	Memory
759306		boyliguanhan	Joker (BOI20_joker)	C++17	31 / 100	2071 ms	22792 KiB

Joker

#include<bits/stdc++.h>
#pragma GCC optimize(2)
using namespace std;
#define N 200100
vector<int> adj[N];
vector<pair<int, int>> arr[N];
int color[N], ans[N], a[N], b[N], n, m, q;
int dfs(int x, int col) {
    if(color[x]) {
        if(col==color[x]) return 0;
        else return 1;
    }
    color[x] = col;
    for(auto i: adj[x]) 
        if(dfs(i, 3-col))
            return 1;
    return 0;
}
bool check(int l, int r) {
    memset(color, 0, sizeof color);
    for(int i = 1; i <= n; i++)
        adj[i].clear();
    for(int i = 0; i < l; i++)
        adj[a[i]].push_back(b[i]), adj[b[i]].push_back(a[i]);
    for(int i = r+1; i < m; i++)
        adj[a[i]].push_back(b[i]), adj[b[i]].push_back(a[i]);
    for(int i = 0; i < n; i++)
        if(!color[i])
            if(dfs(i, 1))
                return 1;
    return 0;
}
int main() {
    cin.sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> m >> q;
    for(int i = 0; i < m; i++)
        cin >> a[i] >> b[i];
    for(int i = 0; i < q; ++i) {
        int l, r;
        cin >> l >> r;
        arr[l-1].push_back({r-1,i});
    }
    for(int i = 0; i < 200; i++) {
        sort(arr[i].begin(), arr[i].end());
        int l = 0, r = arr[i].size();
        while(l<r) {
            int mid = l+r>>1;
            if(check(i, arr[i][mid].first)) {
                l = mid+1;
            } else {
                r = mid;
            }
        }
        for(int j = 0; j < l; j++)
            ans[arr[i][j].second] = 1;
        for(int j = l; j < arr[i].size(); ++j)
            ans[arr[i][j].second] = 0;
    }
    for(int i = 0; i < q; i++)
        cout << (ans[i]?"YES\n":"NO\n");
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:48:24: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   48 |             int mid = l+r>>1;
      |                       ~^~
Joker.cpp:57:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |         for(int j = l; j < arr[i].size(); ++j)
      |                        ~~^~~~~~~~~~~~~~~

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