xor.cpp:19:49: error: 'int index' redeclared as different kind of entity
19 | int pref[N],a[N],trie[N * 31][2],mn[N * 31 * 2],index = 0;
| ^~~~~
In file included from /usr/include/string.h:432,
from /usr/include/c++/10/cstring:42,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:48,
from xor.cpp:1:
/usr/include/strings.h:61:1: note: previous declaration 'const char* index(const char*, int)'
61 | index (const char *__s, int __c) __THROW
| ^~~~~
xor.cpp: In function 'void Add(int, int)':
xor.cpp:25:44: error: no pre-increment operator for type
25 | if(!trie[node][bit]) trie[node][bit] = ++index;
| ^~~~~
xor.cpp: In function 'int get(int, int)':
xor.cpp:32:15: warning: unused variable 'val' [-Wunused-variable]
32 | int node = 0,val = 0,res = inf;
| ^~~