제출 #101584

#제출 시각아이디문제언어결과실행 시간메모리
101584dantoh000007 (CEOI14_007)C++14
0 / 100
406 ms20220 KiB
#include <bits/stdc++.h> using namespace std; const int maxn = 200001; /*const int logn = 18; int p[logn+1][maxn], h[maxn]; int H[maxn]; int d[maxn]; */ vector<int> adjlist[maxn]; /* bitset<maxn> vis; void dfs(int x){ if (vis[x]) return; vis[x] = 1; for (int k = 0; k < logn; k++){ if (p[k][x] == -1) break; p[k+1][x] = p[k][p[k][x]]; } for (auto v : adjlist[x]){ if (vis[v]) continue; //printf("%d -> %d\n",x,v); p[0][v] = x; d[v] = d[x]+1; h[v] = h[x]+1; dfs(v); } } int lca(int a, int b){ if (h[a] > h[b]) swap(a,b); for (int k = 0, d= h[b] - h[a]; k < logn; k++){ if (d & (1<<k)) b = p[k][b]; } if (a==b) return a; assert(h[a] == h[b]); for (int k = logn-1; k >=0; --k){ if (p[k][a] != p[k][b]) a = p[k][a], b = p[k][b]; assert(p[0][a] == p[0][b]); return p[0][a]; } } int anc(int x, int d){ for (int k = 0; k <= logn && x != -1; k++){ if (d & (1<<k)) x = p[k][x]; } return x; } int dist(int a, int b){ return d[a] + d[b] - 2*d[lca(a,b)]; }*/ int ds[maxn][4]; void bfs(int u, int k){ queue<int> q; q.push(u); ds[u][k] = 0; while (q.size()){ int x = q.front(); q.pop(); for (auto v :adjlist[x]){ if (ds[v][k] == -1){ ds[v][k] = ds[x][k]+1; q.push(v); } } } } int main(){ int n,e; scanf("%d%d",&n,&e); int s0, sn, serve1, serve2; scanf("%d%d%d%d",&s0,&sn,&serve1,&serve2); s0--, sn--, serve1--, serve2--; adjlist[serve1].push_back(serve2); adjlist[serve2].push_back(serve1); for (int i = 0; i < e; i++){ int a,b; scanf("%d%d",&a,&b); if ((a == serve1 && b == serve2) || (a==serve2 && b == serve1)) continue; a--; b--; adjlist[a].push_back(b); adjlist[b].push_back(a); } memset(ds,-1,sizeof(ds)); bfs(s0,0); bfs(sn,1); //dfs(s0); //printf("%d %d %d\n",sn,serve1,lca(sn,serve1)); //if (lca(sn,serve1) == s0){ // printf("%d",d[sn]); //} //else{ int dist0 = max(ds[serve1][0],ds[serve2][0]); int distn = min(ds[serve1][1],ds[serve2][1]); //printf("%d %d\n",dist0,distn); if (dist0 > distn) printf("-1"); else printf("%d",distn-dist0); //} }

컴파일 시 표준 에러 (stderr) 메시지

007.cpp: In function 'int main()':
007.cpp:67:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     int n,e; scanf("%d%d",&n,&e);
              ~~~~~^~~~~~~~~~~~~~
007.cpp:69:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d%d%d",&s0,&sn,&serve1,&serve2);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
007.cpp:75:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~
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