Kuhn algorithm

import java.io.*;
import java.util.*;

public class minimax {
    FastScanner in;
    PrintWriter out;

    class Kuhn {
        int n;
        boolean[] used;
        int[] left;

        ArrayList<Integer>[] g;

        public Kuhn(ArrayList<Integer>[] g) {
            super();
            this.n = g.length;
            this.g = g;
            used = new boolean[n];
            left = new int[n];
        }

        boolean tryKuhn(int v) {
            if (used[v])
                return false;
            used[v] = true;
            for (int i = 0; i < g[v].size(); ++i) {
                int to = g[v].get(i);
                if (left[to] == -1 || tryKuhn(left[to])) {
                    left[to] = v;
                    return true;
                }
            }
            return false;
        }

        boolean solve() {
            Arrays.fill(left, -1);
            for (int v = 0; v < n; ++v) {
                Arrays.fill(used, false);
                tryKuhn(v);
            }

            for (int i = 0; i < n; i++)
                if (left[i] == -1)
                    return false;
            return true;
        }

    }

    void solve() {

    }

    void run() {
        try {
            in = new FastScanner(new File("minimax.in"));
            out = new PrintWriter(new File("minimax.out"));

            solve();

            out.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

    void runIO() {

        in = new FastScanner(System.in);
        out = new PrintWriter(System.out);

        solve();

        out.close();
    }

    class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(File f) {
            try {
                br = new BufferedReader(new FileReader(f));
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }

        public FastScanner(InputStream f) {
            br = new BufferedReader(new InputStreamReader(f));
        }

        String next() {
            while (st == null || !st.hasMoreTokens()) {
                String s = null;
                try {
                    s = br.readLine();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (s == null)
                    return null;
                st = new StringTokenizer(s);
            }
            return st.nextToken();
        }

        boolean hasMoreTokens() {
            while (st == null || !st.hasMoreTokens()) {
                String s = null;
                try {
                    s = br.readLine();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (s == null)
                    return false;
                st = new StringTokenizer(s);
            }
            return true;
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }

    public static void main(String[] args) {
        new minimax().run();
    }
}