Submission #88851

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
88851	2018-12-09T08:51:27 Z	sailormoon	Triumphal arch (POI13_luk)	C++14	80 / 100	2000 ms	30308 KB

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

using namespace std;

vector<vector<int>> graph (300001); // size
unordered_set<int> 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

luk.cpp: In function 'int canHandle(int, int)':
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: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);
         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	7 ms	7416 KB	Output is correct
2	Correct	7 ms	7420 KB	Output is correct
3	Correct	7 ms	7496 KB	Output is correct

Subtask #2
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	8 ms	7624 KB	Output is correct
2	Correct	7 ms	7624 KB	Output is correct
3	Correct	7 ms	7624 KB	Output is correct
4	Correct	7 ms	7624 KB	Output is correct
5	Correct	9 ms	7624 KB	Output is correct

Subtask #3
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	11 ms	7744 KB	Output is correct
2	Correct	7 ms	7744 KB	Output is correct
3	Correct	8 ms	7744 KB	Output is correct

Subtask #4
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	9 ms	7744 KB	Output is correct
2	Correct	9 ms	7744 KB	Output is correct
3	Correct	9 ms	7744 KB	Output is correct

Subtask #5
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	32 ms	8316 KB	Output is correct
2	Correct	33 ms	8444 KB	Output is correct
3	Correct	26 ms	8444 KB	Output is correct

Subtask #6
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	263 ms	9980 KB	Output is correct
2	Correct	92 ms	10620 KB	Output is correct
3	Correct	82 ms	10620 KB	Output is correct

Subtask #7
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	652 ms	14860 KB	Output is correct
2	Correct	780 ms	16268 KB	Output is correct
3	Correct	503 ms	16268 KB	Output is correct

Subtask #8
10.0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	1966 ms	22240 KB	Output is correct
2	Correct	1494 ms	25724 KB	Output is correct
3	Correct	885 ms	25724 KB	Output is correct

Subtask #9
0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Execution timed out	2057 ms	30308 KB	Time limit exceeded

Subtask #10
0 / 10.0

#	Verdict	Execution time	Memory	Grader output
1	Execution timed out	2029 ms	30308 KB	Time limit exceeded
2	Halted	0 ms	0 KB	-