/in/foo.cc: In function 'info unite(info, info, bool)':
/in/foo.cc:116:32: warning: narrowing conversion of 'id[i]' from 'int' to 'short int' inside { } [-Wnarrowing]
       ans.e[edge_cnt++] = {id[i], id[j], w};
                            ~~~~^
/in/foo.cc:116:39: warning: narrowing conversion of 'id[j]' from 'int' to 'short int' inside { } [-Wnarrowing]
       ans.e[edge_cnt++] = {id[i], id[j], w};
                                   ~~~~^
/in/foo.cc: In function 'int main()':
/in/foo.cc:155:46: warning: narrowing conversion of 'i' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i, i + 1, column[i][j]};
                                              ^
/in/foo.cc:155:29: warning: narrowing conversion of '(i + 1)' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i, i + 1, column[i][j]};
                           ~~^~~
/in/foo.cc:158:26: warning: narrowing conversion of '(i + n)' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i + n, i + n + 1, column[i][(j + 1) % m]};
                        ~~^~~
/in/foo.cc:158:37: warning: narrowing conversion of '((i + n) + 1)' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i + n, i + n + 1, column[i][(j + 1) % m]};
                               ~~~~~~^~~
/in/foo.cc:161:43: warning: narrowing conversion of 'i' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i, i + n, row[i][j]};
                                           ^
/in/foo.cc:161:29: warning: narrowing conversion of '(i + n)' from 'int' to 'short int' inside { } [-Wnarrowing]
       e[edge_cnt++] = {i, i + n, row[i][j]};
                           ~~^~~