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Submission #1112186

# Submission time Handle Problem Language Result Execution time Memory
1112186 2024-11-13T18:41:55 Z vjudge1 Palembang Bridges (APIO15_bridge) C++17
100 / 100
 115 ms 13492 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <array>
using namespace std;

int main() {
  int K, n;
  cin >> K >> n;

  vector<pair<long long, long long>> citizens;
  long long basicCost = 0;
  for (int i = 0;i < n; ++i) {
    long long x, y;
    char a, b;
    cin >> a >> x >> b >> y;
    if (a == b) {
      basicCost += abs(x-y);
    } else {
      basicCost += 1;
      if (x > y) citizens.push_back({y, x});
      else citizens.push_back({x, y});
    }
  }
  sort(citizens.begin(), citizens.end(), [](const pair<long long, long long>& a, const pair<long long, long long>& b) {
    return a.first + a.second < b.first + b.second;
  });
  vector<array<long long, 3>> points;
  points.push_back({0, -1, -1}); // add a fake point for easy boundary handling.
  for (int i = 0; i < citizens.size(); ++i) {
    points.push_back({citizens[i].first, 0, i});
    points.push_back({citizens[i].second, 1, i});
  }
  sort(points.begin(), points.end());
  /*
  cerr << "init, bcost:" << basicCost << " citizens:" << citizens.size() << endl;
  for (auto p : points) {
    cerr << "dist:" << p[0] << " pt:" << p[1] << "  idx:" << p[2] << endl;
  }
  */

  long long rightCost = 0;
  for (auto& ctz : citizens) {
    rightCost += ctz.first + ctz.second;
  }
  int rightIndex = 0;
  int rightBehind = 0, rightAhead = citizens.size();
  while (rightBehind < rightAhead) {
    ++rightIndex;
    rightCost += (rightBehind - rightAhead) * 2 * (points[rightIndex][0] - points[rightIndex - 1][0]);
    if (points[rightIndex][1] == 0) rightAhead -= 1;
    else if (points[rightIndex][1] == 1) rightBehind += 1;
  }
  if (K == 1) {
    cout << rightCost + basicCost << endl;
    return 0;
  }
  long long bestCost = rightCost;

  long long leftCost = 0;
  int leftIndex = 0, leftAhead = 0, leftBehind = 0;
  for (int mid = 0; mid + 1 < citizens.size(); ++mid) {
    // cerr << "----- " << "round " << mid << endl;
    // Reduce the effect of mid from right side.
    if (array<long long, 3>({citizens[mid].first, 0, mid}) > points[rightIndex]) {
      rightAhead -= 1;
      rightCost -= citizens[mid].first + citizens[mid].second - 2 * points[rightIndex][0];
    } else if (array<long long, 3>({citizens[mid].second, 1, mid}) <= points[rightIndex]) {
      rightBehind -= 1;
      rightCost -= - (citizens[mid].first + citizens[mid].second) + 2 * points[rightIndex][0];
    } else {
      rightCost -= citizens[mid].second - citizens[mid].first;
    }
    while (rightBehind < rightAhead) {
      rightIndex += 1;
      rightCost += (rightBehind - rightAhead) * 2 * (points[rightIndex][0] - points[rightIndex - 1][0]);
      if (points[rightIndex][2] > mid) {
        if (points[rightIndex][1] == 0) rightAhead -= 1;
        else rightBehind += 1;
      }
    }

    // Add the cost of newly added stuff.
    if (array<long long, 3>({citizens[mid].first, 0, mid}) > points[leftIndex]) {
      leftAhead += 1;
      leftCost += citizens[mid].first + citizens[mid].second - 2 * points[leftIndex][0];
    } else if (array<long long, 3>({citizens[mid].second, 1, mid}) <= points[leftIndex]) {
      leftBehind += 1;
      leftCost += - (citizens[mid].first + citizens[mid].second) + 2 * points[leftIndex][0];
    } else {
      leftCost += citizens[mid].second - citizens[mid].first;
    }
    while (leftBehind < leftAhead) {
      leftIndex += 1;
      leftCost += (leftBehind - leftAhead) * 2 * (points[leftIndex][0] - points[leftIndex - 1][0]);
      if (points[leftIndex][2] <= mid) {
        if (points[leftIndex][1] == 0) leftAhead -= 1;
        else leftBehind += 1;
      }
    }
/*
    cerr << "Round: " << mid << endl;
    cerr << rightCost<< ": " << rightIndex << " " << rightAhead << ":" << rightBehind << endl;
    cerr << leftCost << ": " << leftIndex << " " << leftAhead << ":" << leftBehind << endl;
    */
    if (leftCost + rightCost < bestCost) {
      bestCost = leftCost + rightCost;
    }
  }

  cout << bestCost + basicCost << endl;
  return 0;
}

Compilation message

bridge.cpp: In function 'int main()':
bridge.cpp:30:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |   for (int i = 0; i < citizens.size(); ++i) {
      |                   ~~^~~~~~~~~~~~~~~~~
bridge.cpp:62:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |   for (int mid = 0; mid + 1 < citizens.size(); ++mid) {
      |                     ~~~~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 1 ms 336 KB Output is correct
3 Correct 1 ms 560 KB Output is correct
4 Correct 1 ms 336 KB Output is correct
5 Correct 2 ms 508 KB Output is correct
6 Correct 2 ms 336 KB Output is correct
7 Correct 2 ms 336 KB Output is correct
8 Correct 1 ms 336 KB Output is correct
9 Correct 2 ms 336 KB Output is correct
10 Correct 2 ms 336 KB Output is correct
11 Correct 2 ms 336 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 1 ms 336 KB Output is correct
3 Correct 2 ms 336 KB Output is correct
4 Correct 1 ms 336 KB Output is correct
5 Correct 2 ms 336 KB Output is correct
6 Correct 2 ms 336 KB Output is correct
7 Correct 1 ms 336 KB Output is correct
8 Correct 1 ms 336 KB Output is correct
9 Correct 2 ms 336 KB Output is correct
10 Correct 2 ms 336 KB Output is correct
11 Correct 2 ms 336 KB Output is correct
12 Correct 63 ms 11956 KB Output is correct
13 Correct 97 ms 13492 KB Output is correct
14 Correct 63 ms 12212 KB Output is correct
15 Correct 59 ms 6936 KB Output is correct
16 Correct 90 ms 12704 KB Output is correct
17 Correct 76 ms 13432 KB Output is correct
18 Correct 71 ms 12996 KB Output is correct
19 Correct 76 ms 13492 KB Output is correct
20 Correct 73 ms 12980 KB Output is correct
21 Correct 76 ms 13084 KB Output is correct

Subtask #3
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 1 ms 504 KB Output is correct
3 Correct 1 ms 336 KB Output is correct
4 Correct 1 ms 336 KB Output is correct
5 Correct 1 ms 336 KB Output is correct
6 Correct 1 ms 336 KB Output is correct
7 Correct 2 ms 336 KB Output is correct
8 Correct 1 ms 336 KB Output is correct
9 Correct 1 ms 336 KB Output is correct
10 Correct 1 ms 336 KB Output is correct
11 Correct 1 ms 336 KB Output is correct
12 Correct 1 ms 456 KB Output is correct

Subtask #4
32.0 / 32.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 1 ms 336 KB Output is correct
3 Correct 1 ms 336 KB Output is correct
4 Correct 1 ms 336 KB Output is correct
5 Correct 1 ms 336 KB Output is correct
6 Correct 1 ms 504 KB Output is correct
7 Correct 1 ms 444 KB Output is correct
8 Correct 1 ms 336 KB Output is correct
9 Correct 1 ms 336 KB Output is correct
10 Correct 1 ms 336 KB Output is correct
11 Correct 1 ms 504 KB Output is correct
12 Correct 1 ms 336 KB Output is correct
13 Correct 2 ms 336 KB Output is correct
14 Correct 2 ms 336 KB Output is correct
15 Correct 3 ms 336 KB Output is correct
16 Correct 1 ms 336 KB Output is correct
17 Correct 2 ms 336 KB Output is correct
18 Correct 2 ms 336 KB Output is correct
19 Correct 2 ms 336 KB Output is correct
20 Correct 2 ms 336 KB Output is correct
21 Correct 1 ms 448 KB Output is correct
22 Correct 2 ms 348 KB Output is correct
23 Correct 2 ms 336 KB Output is correct
24 Correct 2 ms 336 KB Output is correct

Subtask #5
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 336 KB Output is correct
2 Correct 1 ms 336 KB Output is correct
3 Correct 1 ms 336 KB Output is correct
4 Correct 1 ms 336 KB Output is correct
5 Correct 1 ms 336 KB Output is correct
6 Correct 1 ms 508 KB Output is correct
7 Correct 1 ms 440 KB Output is correct
8 Correct 1 ms 336 KB Output is correct
9 Correct 1 ms 336 KB Output is correct
10 Correct 1 ms 336 KB Output is correct
11 Correct 1 ms 336 KB Output is correct
12 Correct 1 ms 504 KB Output is correct
13 Correct 1 ms 336 KB Output is correct
14 Correct 1 ms 336 KB Output is correct
15 Correct 2 ms 336 KB Output is correct
16 Correct 1 ms 336 KB Output is correct
17 Correct 1 ms 336 KB Output is correct
18 Correct 1 ms 336 KB Output is correct
19 Correct 2 ms 336 KB Output is correct
20 Correct 2 ms 336 KB Output is correct
21 Correct 2 ms 336 KB Output is correct
22 Correct 2 ms 336 KB Output is correct
23 Correct 1 ms 336 KB Output is correct
24 Correct 2 ms 504 KB Output is correct
25 Correct 55 ms 11776 KB Output is correct
26 Correct 65 ms 11944 KB Output is correct
27 Correct 77 ms 12728 KB Output is correct
28 Correct 95 ms 13492 KB Output is correct
29 Correct 115 ms 13476 KB Output is correct
30 Correct 48 ms 6752 KB Output is correct
31 Correct 67 ms 12724 KB Output is correct
32 Correct 69 ms 13492 KB Output is correct
33 Correct 81 ms 12980 KB Output is correct
34 Correct 75 ms 13484 KB Output is correct
35 Correct 72 ms 12972 KB Output is correct
36 Correct 69 ms 13276 KB Output is correct
37 Correct 51 ms 12004 KB Output is correct