oj.uz

Submission #88902

# Submission time Handle Problem Language Result Execution time Memory
88902 2018-12-09T18:49:28 Z sailormoon Triumphal arch (POI13_luk) C++14
90 / 100
 1429 ms 39540 KB 
#include <string>
#include <algorithm>
#include <iostream>
#include <vector>

using namespace std;
int canHandle(int v, int crs, bool visited[]);
vector<vector<int>> graph (1000001); // size

int main() { 
  int n, a, b, start = 0, midpoint, end, cities; // n -> towns, a -> from, b -> to
  scanf("%d", &n);
  cities = n; // for further usage
  end = n; // last point
  n--;
  while (n--) {
    scanf("%d %d", &a, &b);
    graph[a].push_back(b);
    graph[b].push_back(a);
  }

  // binary search for sufficient amount of crews
  while (start < end) {
    bool visited[1000001];
    midpoint = (start + end) / 2;
    for (int i = 0; i < cities; i++) visited[i] = false; // clear array 
    if (canHandle(1, midpoint, visited) == 0) end = midpoint;
    else start = midpoint + 1; 
  }
  printf("%d\n", start);
  return 0;
}

int canHandle(int v, int crs, bool visited[]) {
  int num_children = 0, need_crews = 0;
  visited[v] = true;
  for (int i = 0; i < graph[v].size(); i++) {
    if (!visited[graph[v][i]]) { 
      num_children++;
      need_crews += canHandle(graph[v][i], crs, visited);
    }
  }
  if (num_children + need_crews - crs <= 0)
    return 0;
  return num_children + need_crews - crs;
}

Compilation message

luk.cpp: In function 'int canHandle(int, int, bool*)':
luk.cpp:37:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i = 0; i < graph[v].size(); i++) {
                   ~~^~~~~~~~~~~~~~~~~
luk.cpp: In function 'int main()':
luk.cpp:12:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n);
   ~~~~~^~~~~~~~~~
luk.cpp:17:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &a, &b);
     ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23800 KB Output is correct
2 Correct 22 ms 23932 KB Output is correct
3 Correct 21 ms 23932 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23932 KB Output is correct
2 Correct 22 ms 23932 KB Output is correct
3 Correct 22 ms 23932 KB Output is correct
4 Incorrect 29 ms 23932 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 24080 KB Output is correct
2 Correct 22 ms 24080 KB Output is correct
3 Correct 23 ms 24080 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 24080 KB Output is correct
2 Correct 22 ms 24144 KB Output is correct
3 Correct 22 ms 24144 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 24556 KB Output is correct
2 Correct 29 ms 24556 KB Output is correct
3 Correct 28 ms 24556 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 58 ms 25196 KB Output is correct
2 Correct 59 ms 25980 KB Output is correct
3 Correct 42 ms 25980 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 209 ms 27648 KB Output is correct
2 Correct 151 ms 29308 KB Output is correct
3 Correct 109 ms 29308 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 616 ms 30944 KB Output is correct
2 Correct 588 ms 35580 KB Output is correct
3 Correct 423 ms 35580 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1271 ms 35580 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1429 ms 35580 KB Output is correct
2 Correct 1086 ms 39540 KB Output is correct
3 Correct 409 ms 39540 KB Output is correct