/in/foo.c: In function 'main':
/in/foo.c:5:5: error: unknown type name 'bool'
     bool trees[10001];
     ^~~~
/in/foo.c:7:20: error: 'true' undeclared (first use in this function)
         trees[i] = true;
                    ^~~~
/in/foo.c:7:20: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:13:24: error: 'false' undeclared (first use in this function)
             trees[j] = false;
                        ^~~~~
/in/foo.c:16:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
     for(i = 0;i <= L; i++)
     ^~~
/in/foo.c:18:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
         printf("%d\n", count);
         ^~~~~~