Batch Style Mastermind Validator

#include <sstream>
#include <iostream>
#include <iomanip>
#include <ext/stdio_filebuf.h>
#include <string>
#include <set>
#include <vector>
#include <algorithm>
#include <cstdlib>
#include <climits>
#include <ctime>
using namespace std;

#define lrotl(val,rot) (( (val)<<(rot) )|( (val)>>(sizeof(val)*CHAR_BIT-(rot)) ))
static unsigned int x = 123456789;
static unsigned int y = 362436069;
static unsigned int z = 521288629;
static unsigned int w = 88675123;

unsigned int xor_rand(){
    unsigned int t;
    t=x^(x<<11);
    x=y;y=z;z=w;
    return w=(w^(w>>19)) ^ (t^(t>>8));
}

// http://d.hatena.ne.jp/gintenlabo/20100930/1285859540
void xor_srand(unsigned int seed){
#if 1
    x^=seed;
    y^=lrotl(seed,17);
    z^=lrotl(seed,31);
    w^=lrotl(seed,18);
#else
    x^=lrotl(seed,14);
    y^=lrotl(seed,31);
    z^=lrotl(seed,13);
    w^=seed;
#endif
}

static unsigned int _random(unsigned int max){return xor_rand()%max;}

int _main(ostream &pout,istream &pin){ //actual validator
    xor_srand((unsigned int)time(NULL)^(getpid()<<16));
    string TAG="[Validator] ";
    ostringstream oanswer;
    oanswer<<setw(9)<<setfill('0')<<xor_rand()%1000000000;
    string answer=oanswer.str(),op,tmp;
    cerr<<TAG<<"Answer: "<<answer<<endl<<flush;

    set<string>s;
    int test=0;

    //cerr<<TAG<<"Listening."<<endl<<flush;
    for(;;test++){
        pin>>op;
        if(op=="?"){
            cerr<<TAG<<"<Test>"<<flush;
            if(test==21){
                cerr<<TAG<<"Verdict:"<<endl<<flush;
                cout<<"QueryLimitExceeded"<<endl;
                return 0;
            }
            vector<string> arg;
            vector<pair<int,int> >hit_blow;
            int i,j,k;
            for(i=0;i<9;i++){
                pin>>tmp;
                cerr<<" "<<tmp<<flush;
                if(tmp.length()!=9||find(s.begin(),s.end(),tmp)!=s.end()){
                    cerr<<endl<<TAG<<"Verdict is:"<<endl<<flush;
                    cout<<"RuntimeError"<<endl;
                    return 0;
                }
                arg.push_back(tmp);
                s.insert(tmp);
            }
            cerr<<endl<<flush;
            for(i=0;i<9;i++){
                int hit=0,blow=0;
                for(j=0;j<9;j++)
                    if(answer[j]==arg[i][j])hit++;
                for(j='0';j<='9';j++){ //modifiable
                    int c1=0,c2=0;
                    for(k=0;k<9;k++){
                        if(answer[k]==j)c1++;
                        if(arg[i][k]==j)c2++;
                    }
                    blow+=min(c1,c2);
                }
                hit_blow.push_back(make_pair(hit,blow-hit));
            }
            random_shuffle(hit_blow.begin(),hit_blow.end(),_random);
            ostringstream x;
            for(i=0;i<9;i++){
                if(i)x<<' ';
                x<<hit_blow[i].first;
                x<<' ';
                x<<hit_blow[i].second;
            }
            cerr<<TAG<<"Result: "<<x.str()<<endl<<flush;
            pout<<x.str()<<endl<<flush;
        }else if(op=="!"){
            cerr<<TAG<<"<Challenge> "<<flush;
            pin>>tmp;
            cerr<<tmp<<endl<<flush;
            cerr<<TAG<<"Verdict:"<<endl<<flush;
            if(answer!=tmp){
                cout<<"WrongAnswer"<<endl;
            }else if(10<=test){
                cout<<"Accepted100"<<endl;
            }else{
                cout<<"Accepted150"<<endl;
            }
            return 0;
        }else{
            cerr<<TAG<<"Verdict:"<<endl<<flush;
            cout<<"RuntimeError"<<endl;
            return 0;
        }
    }
    return 0;
}

//Reactive
int main(int argc, char **argv){
    if(argc<2){
        cerr<<"validator [program]"<<endl;
        cerr<<"program must be chmod +x"<<endl;
        return 0;
    }
    const char *cmd=argv[1];

    //Initialize
    int fd_in[2],fd_out[2];
    pipe(fd_in);
    pipe(fd_out);

    int pid=fork();
    if(pid==-1){
        cout<<"InternalError"<<endl;
        return 0;
    }
    if(pid==0){//child
        close(0);
        dup2(fd_in[0],0);
        close(1);
        dup2(fd_out[1],1);
        close(fd_in[0]);
        close(fd_in[1]);
        close(fd_out[0]);
        close(fd_out[1]);
        execl(cmd,cmd,NULL);
        return 0;
    }
    //parent
    close(fd_in[0]);
    close(fd_out[1]);
    FILE *fout=fdopen(fd_in[1],"w");
    FILE *fin=fdopen(fd_out[0],"r");
    __gnu_cxx::stdio_filebuf<char> bout(fout, ios_base::out);
    __gnu_cxx::stdio_filebuf<char> bin(fin, ios_base::in);
    ostream pout(&bout);
    istream pin(&bin);
    _main(pout,pin);
    fclose(fout);
    fclose(fin);
    return 0;
}