foo.cc: In function 'int mt(int, int)':
foo.cc:11:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int kx=k;kx<tr[x].size();kx++){ 
                      ~~^~~~~~~~~~~~~
foo.cc: In function 'void dfs(int)':
foo.cc:30:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(yc[p][j]==tr[p].size() || yc[p][j]==tr[j].size())
            ~~~~~~~~^~~~~~~~~~~~~~
foo.cc:30:46: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(yc[p][j]==tr[p].size() || yc[p][j]==tr[j].size())
                                      ~~~~~~~~^~~~~~~~~~~~~~

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