Submission #420659

#	Time	Username	Problem	Language	Result	Execution time	Memory
420659		SSRS	Arranging Shoes (IOI19_shoes)	C++14	70 / 100	1083 ms	294192 KiB

shoes

#include <bits/stdc++.h>
using namespace std;
const int INF = 1000000;
struct binary_indexed_tree{
  int N;
  vector<int> BIT;
  binary_indexed_tree(int N): N(N), BIT(N + 1, 0){
  }
  void add(int i, int x){
    i++;
    while (i <= N){
      BIT[i] += x;
      i += i & -i;
    }
  }
  int sum(int i){
    int ans = 0;
    while (i > 0){
      ans += BIT[i];
      i -= i & -i;
    }
    return ans;
  }
  int sum(int L, int R){
    return sum(R) - sum(L);
  }
};
bool compare(vector<int> &a, vector<int> &b, int x, int y){
  if (a[x] < a[y] && a[y] < b[x] && b[x] < b[y]){
    return true;
  }
  if (a[y] < a[x] && a[x] < b[y] && b[y] < b[x]){
    return false;
  }
  if (b[x] < a[y]){
    return true;
  }
  if (b[y] < a[x]){
    return false;
  }
  return x < y;
}
void merge_sort(vector<int> &A, vector<int> &a, vector<int> &b, int l, int r){
  if (r - l == 1){
    return;
  }
  int m = (l + r) / 2;
  merge_sort(A, a, b, l, m);
  merge_sort(A, a, b, m, r);
  vector<int> ans;
  int p1 = l, p2 = m;
  while (!(p1 == m && p2 == r)){
    if (p1 == m){
      ans.push_back(A[p2]);
      p2++;
    } else if (p2 == r){
      ans.push_back(A[p1]);
      p1++;
    } else if (compare(a, b, A[p1], A[p2])){
      ans.push_back(A[p1]);
      p1++;
    } else {
      ans.push_back(A[p2]);
      p2++;
    }
  }
  for (int i = 0; i < r - l; i++){
    A[l + i] = ans[i];
  }
}
long long count_swaps(vector<int> S){
  int n = S.size() / 2;
  vector<int> a, b, x;
  map<int, queue<int>> Q;
  for (int i = 0; i < n * 2; i++){
    if (Q[-S[i]].empty()){
      Q[S[i]].push(i);
    } else {
      a.push_back(Q[-S[i]].front());
      b.push_back(i);
      x.push_back(abs(S[i]));
      Q[-S[i]].pop();
    }
  }
  vector<int> A(n);
  for (int i = 0; i < n; i++){
    A[i] = i;
  }
  merge_sort(A, a, b, 0, n);
  vector<int> S2;
  for (int i = 0; i < n; i++){
    S2.push_back(-x[A[i]]);
    S2.push_back(x[A[i]]);
  }
  map<int, queue<int>> Q2;
  for (int i = 0; i < n * 2; i++){
    Q2[S2[i]].push(i);
  }
  vector<int> p;
  for (int i = 0; i < n * 2; i++){
    p.push_back(Q2[S[i]].front());
    Q2[S[i]].pop();
  }
  long long ans = 0;
  binary_indexed_tree BIT(n * 2);
  for (int i = 0; i < n * 2; i++){
    ans += BIT.sum(p[i] + 1, n * 2);
    BIT.add(p[i], 1);
  }
  return ans;
}

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 15