/in/foo.c: In function 'main':
/in/foo.c:5:15: warning: unused variable 'j' [-Wunused-variable]
  int n, m, i, j, count=0, a[100000];
               ^
/in/foo.c: In function 'twoSum':
/in/foo.c:23:24: warning: implicit declaration of function 'malloc' [-Wimplicit-function-declaration]
     int *table = (int*)malloc(len*sizeof(int));
                        ^~~~~~
/in/foo.c:23:24: warning: incompatible implicit declaration of built-in function 'malloc'
/in/foo.c:23:24: note: include '<stdlib.h>' or provide a declaration of 'malloc'
/in/foo.c:35:5: warning: implicit declaration of function 'free' [-Wimplicit-function-declaration]
     free(table);
     ^~~~
/in/foo.c:35:5: warning: incompatible implicit declaration of built-in function 'free'
/in/foo.c:35:5: note: include '<stdlib.h>' or provide a declaration of 'free'