| 3 | vi adj[MAXV]; |
| 4 | int n, m, indeg[MAXV], outdeg[MAXV], res[MAXE + 1]; |
| 5 | ii start_end() { |
| 6 | int start = -1, end = -1, any = 0, c = 0; |
| 7 | rep(i,0,n) { |
| 8 | if (outdeg[i] > 0) any = i; |
| 9 | if (indeg[i] + 1 == outdeg[i]) start = i, c++; |
| 10 | else if (indeg[i] == outdeg[i] + 1) end = i, c++; |
| 11 | else if (indeg[i] != outdeg[i]) return ii(-1,-1); } |
| 12 | if ((start == -1) != (end == -1) || (c != 2 && c != 0)) |
| 13 | return ii(-1,-1); |
| 14 | if (start == -1) start = end = any; |
| 15 | return ii(start, end); } |
| 16 | bool euler_path() { |
| 17 | ii se = start_end(); |
| 18 | int cur = se.first, at = m + 1; |