제출 #731098

#제출 시각아이디문제언어결과실행 시간메모리
731098Ivo_12Torrent (COI16_torrent)C++98
0 / 100
451 ms19132 KiB
#include <bits/stdc++.h> using namespace std; int n, a, b, x, y; vector < int > connections[300010]; vector < int > trail; bool find_trail( int prev, int cur ) { if(cur == b) { trail.push_back(cur); return 1; } for(int i = 0; i < connections[cur].size(); i++) { if(connections[cur][i] != prev) { if(find_trail(cur, connections[cur][i])) { trail.push_back(cur); return 1; } } } return 0; } int efficient( int last, int cur, int cut ) { vector < int > tempmem; if(last == connections[cur][0] && connections[cur].size() == 1) return 0; if(cut == connections[cur][0] && connections[cur].size() == 1) return 0; if(connections[cur].size()==2) { if(cut == connections[cur][0] && last == connections[cur][1]) return 0; if(last == connections[cur][0] && cut == connections[cur][1]) return 0; } for(int i = 0; i < connections[cur].size(); i++) { if(connections[cur][i] != last && connections[cur][i] != cut) tempmem.push_back(efficient(cur, connections[cur][i], cut)); } sort(tempmem.begin(), tempmem.end()); // cout << cur << " "; for(int i = 0; i < (tempmem.size()); i++) { tempmem[i] += (tempmem.size())-i; // cout << tempmem[i] << " "; } // cout << "\n"; return *max_element(tempmem.begin(), tempmem.end()); } int binary_search( void ) { int l = 0; int r = trail.size() - 2; int mid; while(r > l) { mid = l + (r - l) / 2; if(efficient(-1, a, trail[mid]) >= efficient(-1, b, trail[mid+1])) r = mid; else l = mid + 1; } return max(efficient(-1, a, trail[l]), efficient(-1, b, trail[l+1])); // greska, run time error i trebas isprobati za l-1 s obzirom da vracas prvi veci a mozda ce i prvi manji biti dobar } int main( void ) { cin >> n >> a >> b; for(int i = 0; i < n-1; i++) { cin >> x >> y; connections[x].push_back(y); connections[y].push_back(x); } find_trail(-1, a); // for(int i = 0; i < trail.size(); i++) { // cout << trail[i] << " "; // } cout << binary_search(); return 0; }

컴파일 시 표준 에러 (stderr) 메시지

torrent.cpp: In function 'bool find_trail(int, int)':
torrent.cpp:14:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |  for(int i = 0; i < connections[cur].size(); i++) {
      |                 ~~^~~~~~~~~~~~~~~~~~~~~~~~~
torrent.cpp: In function 'int efficient(int, int, int)':
torrent.cpp:33:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  for(int i = 0; i < connections[cur].size(); i++) {
      |                 ~~^~~~~~~~~~~~~~~~~~~~~~~~~
torrent.cpp:38:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |  for(int i = 0; i < (tempmem.size()); i++) {
      |                 ~~^~~~~~~~~~~~~~~~~~
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