paint.cpp: In function 'void pre()':
paint.cpp:17:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=1; i<=s.length(); i++){
~^~~~~~~~~~~~
paint.cpp: In function 'bool solve(int, int)':
paint.cpp:40:6: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(u>=s.length() && ind<n) return false;
~^~~~~~~~~~~~
paint.cpp:45:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(u+t-1<s.length() && w[u+t-1]==0 && s[u+t]!='X'){
~~~~~^~~~~~~~~~~
paint.cpp:56:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(u+t-1<s.length() && w[u+t-1]-w[u-1]==0 && s[u+t]!='X'){
~~~~~^~~~~~~~~~~
paint.cpp: In function 'std::__cxx11::string solve_puzzle(std::__cxx11::string, std::vector<int>)':
paint.cpp:80:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=1; i<ss.length(); i++){
~^~~~~~~~~~~~
paint.cpp:85:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
for(int i=0; i<ss.length(); i++){
~^~~~~~~~~~~~