messy.cpp: In function 'std::string sum(std::string&, std::string&)':
messy.cpp:13:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
13 | for(int i=0;i<b.size();i++){
| ~^~~~~~~~~
In file included from /usr/include/c++/10/cassert:44,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:33,
from messy.cpp:2:
messy.cpp: In function 'std::vector<int> restore_permutation(int, int, int)':
messy.cpp:25:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
25 | assert(x.size()==N);
| ~~~~~~~~^~~
messy.cpp:36:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
36 | assert(x.size()==N);
| ~~~~~~~~^~~
messy.cpp:50:28: warning: comparison of integer expressions of different signedness: 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
50 | assert(k.size()==N);
| ~~~~~~~~^~~