Checker

#include "testlib.h"
#include<bits/stdc++.h>

using namespace std;

int main(int argc, char* argv[]) {
    registerTestlibCmd(argc, argv);

    int n = inf.readInt();
    int m = inf.readInt();

    vector<vector<int>> s(n + 1, vector<int>());
    map<int, bool> M;
    int cnt = 0;

    for(int i = 1, x, y; i <= m; i++) {
        x = inf.readInt();
        y = inf.readInt();
        s[y].push_back(x);
    }

    if (ans.readToken() == "IMPOSSIBLE") {
        if (ouf.readToken() == "IMPOSSIBLE") {
            quitf(_ok, "Correct: No solution exists");
        } else {
            quitf(_wa, "Wrong answer: Solution exists, but participant claims impossible");
        }
    }

    for(int i = 1, x; i <= n; i++) {
        x = ouf.readInt();
        if(M[x]) {
            quitf(_wa, "So xuat hien nhieu hon 1 lan");
        }
        for(auto y : s[x]) {
            if(!M[y])
                quitf(_wa, "yeu kem");
        }
        M[x] = 1;
    }

    quitf(_ok, "good");
}

#ifndef __EMITTED_VALIDATE_H
#define __EMITTED_VALIDATE_H

#include <bits/stdc++.h>

typedef void (*feedback_function)(const char*, ...);

const int EXITCODE_AC = 0;
const int EXITCODE_WA = 0;

// declare a constant to be used as user_out.
const std::string FILENAME_USER_OUTPUT = "user_out";
// declare a constant to be used as input.
const std::string FILENAME_INPUT = "input";

#define USAGE "./%s\n"
// we have to define USAGE as dummy because we don't want to modify the lib. too much.

std::ifstream judge_in, judge_ans;
// another ifstream must be used for user_out;
std::ifstream user_out;

char *feedbackdir = NULL;

void vreport_feedback(const char* msg, va_list pvar) {
    assert(stderr);
    vfprintf(stderr, msg, pvar);
}

void report_feedback(const char* msg, ...) {
    va_list pvar;
    va_start(pvar, msg);
    vreport_feedback(msg, pvar);
}

void judge_message(const char* msg, ...) {
    va_list pvar;
    va_start(pvar, msg);
    vreport_feedback(msg, pvar);
}

void judge_error(const char* msg, ...) {
    va_list pvar;
    va_start(pvar, msg);
    vreport_feedback(msg, pvar);
    assert(0);
}

// cleaning up.
void cleanup() {
    fflush(stderr);
    fclose(stderr);
    fflush(stdout);
    fclose(stdout);
    judge_in.close();
    user_out.close();
}

// write another function ``scoring()`` for ac or wa.
void scoring(double score) {
    fprintf(stdout, "%.f", score + 1e-9);
}

void accept() {
    scoring(100.);
    cleanup();
    exit(EXITCODE_AC);
}

void accept_with_score(double scorevalue) {
    scoring(scorevalue);
    cleanup();
    exit(EXITCODE_AC);
}

void wrong_answer(const char* msg, ...) {
    va_list pvar;
    va_start(pvar, msg);
    vreport_feedback(msg, pvar);
    scoring(0.);
    cleanup();
    exit(EXITCODE_WA);
}

void init_io() {
    judge_in.open(FILENAME_INPUT, std::ios_base::in);
    if(judge_in.fail()) {
        judge_error("failed to open input file.\n");
    }
    user_out.open(FILENAME_USER_OUTPUT, std::ios_base::in);
    if(user_out.fail()) {
        judge_error("failed to open user output file.\n");
    }
    judge_ans.open("answer", std::ios_base::in);
    if(judge_ans.fail()) {
        judge_error("failed to open answer file.\n");
    }
}
using namespace std;
void OK(istream &ouf, feedback_function waf) {
    string t;
    if (ouf >> t)
        waf("Sai. Du lieu ra khong dung dinh dang.\n");
    judge_message("OK. Dap an duoc chap nhan!\n");
}

bool check(istream &inf, istream &ans, istream &ouf, feedback_function waf) {
    int n, m;
    inf >> n >> m;
    vector<pair<int, int> > e(m, {0, 0});
    for (int i = 0; i < m; i++)
        inf >> e[i].first >> e[i].second;
    int id[101];
    bool used[101];
    memset(used, 0, sizeof used);
    for (int i = 1; i <= n; i++) {
        if (!(ouf >> id[i]))
            waf("Sai. Du lieu ra khong dung dinh dang!\n");
        if (id[i] < 1 || id[i] > n)
            waf("Sai. Dinh thu %d là %d khong dung!\n", i, id[i]);
        if (used[id[i]])
            waf("Sai. Dinh %d da duoc dung!\n", id[i]);
        used[id[i]] = 1;
    }
    for (pair<int, int> x : e)
        if (id[x.first] > id[x.second])
            waf("Sai. Khong thoa man dieu kien!\n");
    OK(ouf, waf);
    return 1;
}
#endif

int main(void) {
    init_io();
    check(judge_in, judge_ans, user_out, wrong_answer);
    accept();
}