Submission #88846

#	Time	Username	Problem	Language	Result	Execution time	Memory
88846		sailormoon	Triumphal arch (POI13_luk)	C++14	Compilation error	0 ms	0 KiB

luk

#include <map>
#include <string>
#include <algorithm>
#include <iostream>
#include <vector>
#include <set>

using namespace std;

vector<vector<int>> graph (300001); // size
set visited;

int canHandle(int v, int crs) {
    int num_children = 0, need_crews = 0;

    visited.insert(v);

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

int main() { 
    int n, a, b, start = 0, midpoint, end; // n -> towns, a -> from, b -> to
    scanf("%d", &n);
    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;
        if (canHandle(1, midpoint) == 0) 
            end = midpoint;
        else   
            start = ++midpoint; 
        visited.clear();
    }
    printf("%d\n", start);

    return 0;
}

Compilation message (stderr)

luk.cpp:11:1: error: invalid use of template-name 'std::set' without an argument list
 set visited;
 ^~~
luk.cpp:11:1: note: class template argument deduction is only available with -std=c++1z or -std=gnu++1z
In file included from /usr/include/c++/7/set:61:0,
                 from luk.cpp:6:
/usr/include/c++/7/bits/stl_set.h:93:11: note: 'template<class _Key, class _Compare, class _Alloc> class std::set' declared here
     class set
           ^~~
luk.cpp: In function 'int canHandle(int, int)':
luk.cpp:16:5: error: 'visited' was not declared in this scope
     visited.insert(v);
     ^~~~~~~
luk.cpp:18:23: 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:46:9: error: 'visited' was not declared in this scope
         visited.clear();
         ^~~~~~~
luk.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~
luk.cpp:34:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d", &a, &b);
         ~~~~~^~~~~~~~~~~~~~~~~