/in/foo.c:2:1: error: unknown type name 'using'
 using namespace std;
 ^~~~~
/in/foo.c:2:17: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'std'
 using namespace std;
                 ^~~
/in/foo.c:5:1: error: unknown type name 'bool'
 bool go;
 ^~~~
/in/foo.c: In function 'paixu':
/in/foo.c:12:30: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
 if ((a[i]>a[j])||(a[i]==a[j])&&(b[i]>b[j]))
                  ~~~~~~~~~~~~^~~~~~~~~~~~~
/in/foo.c: In function 'main':
/in/foo.c:32:21: error: 'false' undeclared (first use in this function)
 ans=1;time=0;k=1;go=false;
                     ^~~~~
/in/foo.c:32:21: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:42:4: error: 'true' undeclared (first use in this function)
 go=true;
    ^~~~
/in/foo.c:45:3: error: expected expression before 'long'
 t=long(a[k]-time);
   ^~~~