oj.uz

Submission #88875

# Submission time Handle Problem Language Result Execution time Memory
88875 2018-12-09T17:05:14 Z sailormoon Triumphal arch (POI13_luk) C++14
90 / 100
 1381 ms 87728 KB 
#include <string>
#include <algorithm>
#include <iostream>
#include <vector>
#include <unordered_set>

using namespace std;
int canHandle(int v, int crs);
vector<vector<int>> graph (3000001); // size
bool visited[3000001];


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) {
        midpoint = (start + end) / 2;
        for (int i = 0; i < cities; i++) visited[i] = false; // clear array 
        if (canHandle(1, midpoint) == 0) 
            end = midpoint;
        else   
            start = ++midpoint; 
    }
    printf("%d\n", start);

    return 0;
}

int canHandle(int v, int crs) {
    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);
        }
    }
    return max(0, num_children + need_crews - crs);
}

Compilation message

luk.cpp: In function 'int canHandle(int, int)':
luk.cpp:45:23: 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:15:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
luk.cpp:21:14: 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 70 ms 70776 KB Output is correct
2 Correct 67 ms 70784 KB Output is correct
3 Correct 70 ms 70848 KB Output is correct

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 70 ms 70852 KB Output is correct
2 Correct 71 ms 70856 KB Output is correct
3 Correct 74 ms 70860 KB Output is correct
4 Incorrect 73 ms 70980 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 70 ms 70980 KB Output is correct
2 Correct 70 ms 70980 KB Output is correct
3 Correct 64 ms 70980 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 64 ms 71000 KB Output is correct
2 Correct 65 ms 71008 KB Output is correct
3 Correct 69 ms 71072 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 78 ms 71568 KB Output is correct
2 Correct 80 ms 71692 KB Output is correct
3 Correct 77 ms 71788 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 108 ms 72628 KB Output is correct
2 Correct 102 ms 73668 KB Output is correct
3 Correct 223 ms 73668 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 230 ms 75688 KB Output is correct
2 Correct 201 ms 76920 KB Output is correct
3 Correct 217 ms 76920 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 721 ms 79144 KB Output is correct
2 Correct 544 ms 83084 KB Output is correct
3 Correct 258 ms 83084 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1381 ms 83244 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1372 ms 83244 KB Output is correct
2 Correct 1155 ms 87728 KB Output is correct
3 Correct 616 ms 87728 KB Output is correct