View Compilation Error

0_0_32178691_6490.cpp: In function 'void add(int, int)':
0_0_32178691_6490.cpp:34:5: error: 'nex' was not declared in this scope
     nex[e]=beg[x];
     ^
0_0_32178691_6490.cpp: In function 'void dfs1(int, int, int)':
0_0_32178691_6490.cpp:125:27: error: 'nex' was not declared in this scope
     for(Rint i=beg[x];i;i=nex[i]){
                           ^
0_0_32178691_6490.cpp: In function 'void dfs2(int, int)':
0_0_32178691_6490.cpp:140:27: error: 'nex' was not declared in this scope
     for(Rint i=beg[x];i;i=nex[i]){
                           ^