Submission #720157

#	Time	Username	Problem	Language	Result	Execution time	Memory
720157		fuad27	Xor Sort (eJOI20_xorsort)	C++17	100 / 100	10 ms	972 KiB

xorsort

#include<bits/stdc++.h>
using namespace std;
int main () {
  int n, s;
  cin >> n >> s;
  int a[n];
  for(int i = 0;i<n;i++)cin >> a[i];
  vector<pair<int,int>> op;
  if(s==2) {
    for(int i = 19;i>=0;i--) {
      for(int j = 1;j<n;j++) {
        if((a[j]&(1<<i))==0 and (a[j-1]&(1<<i))!=0) {
          a[j]^=a[j-1];
          op.push_back({j,j-1});
        }
        if((a[j-1]&(1<<i))!=0) {
          if((a[j-1]^a[j])<a[j-1]) {
            a[j-1]^=a[j];
            op.push_back({j-1,j});
          }
        }
      }
    }
    cout << op.size() << "\n";
    for(auto i:op) {
      cout << i.first+1 << " " << i.second+1 << "\n";
    }
  }
  else {
    int x=0;
    for(int i = 0;i<n-1;i++) {
      int mx=0;
      for(int j = 0;j<n-i;j++) {
        if((a[j]^x)>(a[mx]^x))mx=j;
      }
      for(int j = 0;j<n-i;j++) {
        if(j!=n-1) {
          op.push_back({j,j+1});
          a[j]^=a[j+1];
        }
      }
      for(int j = mx;j<n-i-1;j++) {
        a[j+1]^=a[j];
        op.push_back({j+1,j});
      }
      for(int j = mx-2;j>=0;j--) {
        a[j]^=a[j+1];
        op.push_back({j,j+1});
      }
      x=a[n-i-1];
    }
    a[0]^=a[1];
    op.push_back({0,1});
    cout << op.size() << "\n";
    for(auto i:op) {
      cout << i.first+1 << " " << i.second+1 << "\n";
    }
  }
}

• Subtask 1: 25 / 25
• Subtask 2: 35 / 35
• Subtask 3: 40 / 40