Submission #1001071

#	Time	Username	Problem	Language	Result	Execution time	Memory
1001071		Unforgettablepl	Chameleon's Love (JOI20_chameleon)	C++17	4 / 100	20 ms	856 KiB

chameleon

#include <bits/stdc++.h>
using namespace std;
 
int Query(const std::vector<int> &p);
void Answer(int a, int b);
 
void Solve(int N) {
    int n = N;
    vector<vector<int>> adj(2*n+1);
    set<pair<int,int>> edges;
    vector<vector<int>> sets;
    for(int i=1;i<=2*n;i++){
        // Find all edges which correspond to
    	sets = vector<vector<int>>(2);
    	vector<bool> visited(2*n+1);
    	function<void(int,int)> dfs = [&](int x,int col){
    		if(visited[x])return;
    		visited[x]=true;
    		sets[col].emplace_back(x);
    		for(int&i:adj[x])dfs(i,(col+1)%2);
    	};
    	for(int j=1;j<i;j++)dfs(j,0);
	    for(int arr=0;arr<2;arr++){
	    	vector<int> msuspects=sets[arr];
	        while(true){
	            auto base = msuspects.size();
	            msuspects.emplace_back(i);
	            if(Query(msuspects)>base)break;
	            msuspects.erase(--msuspects.end());
	            auto suspects = msuspects;
	            while(suspects.size()>1){
	                int mid = suspects.size()/2;
	                vector<int> left,right;
	                for(int i=0;i<mid;i++)left.emplace_back(suspects[i]);
	                for(int i=mid;i<suspects.size();i++)right.emplace_back(suspects[i]);
	                auto b = left.size();
	                left.emplace_back(i);
	                if(Query(left)>b)suspects=right;
	                else {
	                    left.erase(--left.end());
	                    suspects = left;
	                }
	            }
	            msuspects.erase(lower_bound(msuspects.begin(),msuspects.end(),suspects[0]));
	            edges.insert({min(i,suspects[0]),max(i,suspects[0])});
	            adj[i].emplace_back(suspects[0]);
	            adj[suspects[0]].emplace_back(i);
	        }
        }
    }
    for(int i=1;i<=2*n;i++){
        if(adj[i].size()==1)continue;
        assert(adj[i].size()==3);
        if(Query({i,adj[i][0],adj[i][1]})==1)edges.erase({min(i,adj[i][2]),max(i,adj[i][2])});
        else if(Query({i,adj[i][0],adj[i][2]})==1)edges.erase({min(i,adj[i][1]),max(i,adj[i][1])});
        else edges.erase({min(i,adj[i][0]),max(i,adj[i][0])});
    }
    for(auto[a,b]:edges)Answer(a,b);
}

Compilation message (stderr)

chameleon.cpp: In function 'void Solve(int)':
chameleon.cpp:28:33: warning: comparison of integer expressions of different signedness: 'int' and 'long unsigned int' [-Wsign-compare]
   28 |              if(Query(msuspects)>base)break;
      |                 ~~~~~~~~~~~~~~~~^~~~~
chameleon.cpp:35:33: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |                  for(int i=mid;i<suspects.size();i++)right.emplace_back(suspects[i]);
      |                                ~^~~~~~~~~~~~~~~~
chameleon.cpp:38:32: warning: comparison of integer expressions of different signedness: 'int' and 'long unsigned int' [-Wsign-compare]
   38 |                  if(Query(left)>b)suspects=right;
      |                     ~~~~~~~~~~~^~

• Subtask 1: 4 / 4
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36