Submission #707797

#	Time	Username	Problem	Language	Result	Execution time	Memory
707797		victor_gao	Minerals (JOI19_minerals)	C++17	85 / 100	41 ms	2892 KiB

minerals

#include"minerals.h"
#include<bits/stdc++.h>
using namespace std;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
vector<int>arr;
bool alive[100015],vis[100015];
const int C=19;
int n;
void brute(vector<int>arr1,vector<int>arr2,bool stay){
    stay^=1;
    shuffle(arr1.begin(),arr1.end(),rng);
    shuffle(arr2.begin(),arr2.end(),rng);
   // cout<<"Brute : \n";
   // for (auto i:arr1) cout<<i<<" ";
   // cout<<'\n';
   // for (auto i:arr2) cout<<i<<' ';
   // cout<<'\n';
    int sz=arr1.size();
    for (auto i:arr2){
        int last=Query(i),use=0;
        shuffle(arr1.begin(),arr1.end(),rng);
        for (auto j:arr1){
            if (vis[j]) continue;
            if (use==sz-1){
                Answer(i,j);
                break;
            }
            alive[j]^=1;
            int now=Query(j);
            if (stay==1){
                if (now==last){
                 //   cout<<"match1 "<<i<<" "<<j<<'\n';
                    Answer(i,j);
                    vis[j]=1;
                    break;
                }
            }
            else {
                if (now!=last){
                 //   cout<<"match2 "<<i<<" "<<j<<'\n';
                    Answer(i,j);
                    vis[j]=1;
                    break;
                }
            }
            last=now;
        }
        sz--;
    }
}
void Merge(int l,int r,vector<int>have,bool stay1,bool stay2){
    if (r-l+1<=C){
        vector<int>now;
        for (int i=l-1;i<r;i++)
            now.push_back(arr[i]);
        brute(now,have,stay2);
        return;
    }
   /*
    if (l==r){
        Answer(arr[l-1],have[0]);
        return;
    }
    */
    int mid=(l+r)>>1,last;
    vector<int>L,R;
    if (!stay1){
        for (int i=l-1;i<mid;i++){
            last=Query(arr[i]);
            alive[arr[i]]^=1;
        }
    }
    else {
        for (int i=mid;i<r;i++){
            last=Query(arr[i]);
            alive[arr[i]]^=1;
        }
    }
    for (auto i:have){
        int now=Query(i);
        alive[i]^=1;
        bool ty=(now==last);
        if (ty)
            L.push_back(i);
        else R.push_back(i);
        last=now;
    }
    Merge(mid+1,r,R,0,stay2^1);
    Merge(l,mid,L,1,stay2^1);
}
void Solve(int N){
    n=N;
    vector<int>qry;
    int last=-1;
    for (int i=1;i<=2*N;i++){
        int now=Query(i);
        if (now==last){
            qry.push_back(i);
        }
        else {
            arr.push_back(i);
            last=now;
        }
        alive[i]=1;
    }
    //for (auto i:arr) cout<<i<<" ";
    //cout<<'\n';
    //for (auto i:qry) cout<<i<<" ";
    //cout<<'\n';
    Merge(1,N,qry,1,1);
}
/*
g++ -std=gnu++14 -O2 -o grader grader.cpp minerals.cpp
./grader.exe
./rand.exe

4
1 5
2 6
3 4
7 8
*/

Compilation message (stderr)

minerals.cpp: In function 'void Merge(int, int, std::vector<int>, bool, bool)':
minerals.cpp:83:9: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized]
   83 |         if (ty)
      |         ^~

• Subtask 1: 6 / 6
• Subtask 2: 25 / 25
• Subtask 3: 9 / 9
• Subtask 4: 30 / 30
• Subtask 5: 5 / 5
• Subtask 6: 5 / 5
• Subtask 7: 5 / 5
• Subtask 8: 0 / 5
• Subtask 9: 0 / 10