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IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#407589#2296. Exchange StudentsAndycipationWA 1ms3596kbC++203.3kb2024-05-09 02:24:212024-05-09 02:24:23

Judging History

你现在查看的是最新测评结果

  • [2024-05-09 02:24:23]
  • 评测
  • 测评结果:WA
  • 用时:1ms
  • 内存:3596kb
  • [2024-05-09 02:24:21]
  • 提交

answer

/*
 * author:  ADMathNoob
 * created: 05/08/24 14:04:52
 * problem: https://qoj.ac/problem/2296
 */

/*
Comments about problem:


*/

#include <bits/stdc++.h>

using namespace std;

#ifdef _DEBUG
#include "debug.h"
#else
#define debug(...) 42
#endif

template <typename T>
class Fenwick {
 public:
  const int n;
  const int max_power; // smallest power of 2 larger than n
  vector<T> tree;

  Fenwick(int _n) : n(_n), max_power(1 << (32 - __builtin_clz(n))), tree(n) {
    assert(n > 0);
  }

  T get(int x) const {
    assert(-1 <= x && x < n);
    T res{};
    while (x >= 0) {
      res += tree[x];
      x = (x & (x + 1)) - 1;
    }
    return res;
  }

  void modify(int x, T v) {
    assert(0 <= x && x < n);
    while (x < n) {
      tree[x] += v;
      x |= (x + 1);
    }
  }

  /*
  returns the first index p such that sum(a[0..p]) >= t
  returns -1 if the empty sum works and n if no sum works

  NOTE: it only makes sense to use this function when all values
  in the array we are maintaining are non-negative;
  this method allows such queries in O(log(n)) instead of O(log^2(n))
  */
  int lower_bound(T t) const {
    if (t <= 0) {
      return -1;
    }
    int k = -1;
    T sum = 0;
    for (int p = max_power; p > 0; p >>= 1) {
      if (k + p < n && sum + tree[k + p] < t) {
        k += p;
        sum += tree[k];
      }
    }
    return k + 1;
  }
};

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  map<int, vector<int>> pos1;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    pos1[x].push_back(i);
  }
  map<int, vector<int>> pos2;
  for (int i = 0; i < n; i++) {
    int x;
    cin >> x;
    pos2[x].push_back(i);
  }
  Fenwick<int> ft1(n), ft2(n);
  set<int> alive;
  for (int i = 0; i < n; i++) {
    ft1.modify(i, +1);
    ft2.modify(i, +1);
    alive.insert(i);
  }
  vector<pair<int, int>> ops;
  const int OPS = 200000;
  long long ans = 0;
  for (auto [h, st] : pos1) {
    auto fin = pos2[h];
    int k = st.size();
    for (int z = 0; z < k; z++) {
      ans += abs(ft2.get(fin[z]) - ft1.get(st[z]));
    }

    set<int> goL, goR;
    for (int z = 0; z < k; z++) {
      if (ft1.get(st[z]) > ft2.get(fin[z])) {
        goL.insert(z);
      }
      if (ft1.get(st[z]) < ft2.get(fin[z])) {
        goR.insert(z);
      }
    }
    for (int z = 0; z < k; z++) {
      ft1.modify(st[z], -1);
      ft2.modify(fin[z], -1);
    }
    while ((int) ops.size() < OPS && (!goL.empty() || !goR.empty())) {
      if (!goL.empty()) {
        int z = *goL.begin();
        goL.erase(goL.begin());
        auto jt = alive.find(st[z]);
        --jt;
        ops.emplace_back(st[z], *jt);
        st[z] = *jt;
        if (*jt != fin[z]) {
          goL.insert(z);
        }
      } else {
        int z = *prev(goR.end());
        goR.erase(prev(goR.end()));
        auto jt = alive.find(st[z]);
        ++jt;
        ops.emplace_back(st[z], *jt);
        st[z] = *jt;
        if (*jt != fin[z]) {
          goR.insert(z);
        }
      }
    }
    for (int i : fin) {
      alive.erase(i);
    }
  }
  cout << ans << '\n';
  for (auto [x, y] : ops) {
    cout << x + 1 << ' ' << y + 1 << '\n';
  }
  return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 0ms
memory: 3536kb

input:

1
279122803
279122803

output:

0

result:

ok good

Test #2:

score: 0
Accepted
time: 0ms
memory: 3532kb

input:

2
212545283 896408766
212545283 896408766

output:

0

result:

ok good

Test #3:

score: 0
Accepted
time: 1ms
memory: 3592kb

input:

4
3 1 2 4
4 2 1 3

output:

2
2 3
1 4

result:

ok good

Test #4:

score: -100
Wrong Answer
time: 1ms
memory: 3596kb

input:

6
5 1 2 3 4 6
6 4 3 2 1 5

output:

7
2 3
3 4
4 5
3 4
4 3
1 6

result:

wrong output format Unexpected end of file - int32 expected