HDU 1269 STL 自娱自乐

#include <cstdio>#include <cstdlib>#include <cassert>#include <algorithm>#include <queue>#include <vector>using namespace std;vector <vector <int> > adjacence;int vertexSz;int edgeSz;vector <int> topoOrd;vector <bool> isOpened;void DFS(int src){ if(isOpened[src]) return; isOpened[src] = true; for(int i=0; i<adjacence[src].size(); ++i) DFS(adjacence[src][i]); topoOrd.push_back(src);}bool IsStronglyConnected(){ topoOrd.clear(); isOpened.resize(vertexSz); fill(isOpened.begin(), isOpened.end(), false); DFS(0); if(find(isOpened.begin(), isOpened.end(), false) != isOpened.end()) return false; fill(isOpened.begin(), isOpened.end(), false); DFS(topoOrd[0]); if(find(isOpened.begin(), isOpened.end(), false) != isOpened.end()) return false; return true;}int main(){ while(scanf("%d%d", &vertexSz, &edgeSz) != EOF) { if(vertexSz == 0 && edgeSz == 0) break; adjacence.resize(vertexSz); for(int i=0; i<adjacence.size(); ++i) adjacence[i].clear(); for(int i=0; i<edgeSz; ++i) { int f, t; scanf("%d%d", &f, &t); --f, --t; adjacence[f].push_back(t); } if(IsStronglyConnected()) printf("Yes/n"); else printf("No/n"); } return 0;}