Genetic Algorithm

package codechef;

import java.util.*;

public class Demo {

    static ArrayList<Integer> a = new ArrayList<Integer>();
    static ArrayList<Integer> fx = new ArrayList<Integer>();
    static ArrayList<Double> probi = new ArrayList<Double>();
    static ArrayList<Double> ei = new ArrayList<Double>();
    static ArrayList<Integer> ac = new ArrayList<Integer>();

    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);

        System.out.println("Enter the number of initial chromosomes");
        int n = sc.nextInt();
        System.out.println("Enter the initial population");

        for (int i = 0; i < n; i++) {
            a.add(sc.nextInt());
        }

        int sum = 0;
        int max = 0;
        double avg = 0;
        for (int i = 0; i < n; i++) {
            int temp = a.get(i) * a.get(i);
            fx.add(temp);
            sum = sum + temp;
            if (temp >= max) {
                max = temp;
            }
        }

        avg = sum / n;

        for (int i = 0; i < n; i++) {
            double temp = (double) fx.get(i) / sum;
            probi.add(temp);

        }

        for (int i = 0; i < n; i++) {
            double temp = fx.get(i) / avg;
            ei.add(temp);
            if (Math.ceil(temp) - temp <= temp - Math.floor(temp)) {
                ac.add((int) Math.ceil(temp));
            } else {
                ac.add((int) Math.floor(temp));
            }

        }

        print();

        //Step 2
        int k = 0;
        for (int i = 0; i < n; i++) {
            if (ac.get(i) != 0) {
                for (int j = 0; j < ac.get(i); j++) {
                    int temp = a.get(i);
                    a.set(k, temp);
                    k++;
                }
            }
        }

        print();
        //Cross over rate = 50%

        char finalc1[] = new char[4];
        char finalc2[] = new char[4];

        for (int i = 0; i < finalc1.length; i++) {
            finalc1[i] = '0';
        }

        for (int i = 0; i < finalc2.length; i++) {
            finalc2[i] = '0';
        }

        for (int i = 0; i < n / 2; i++) {
            String s1 = Integer.toBinaryString(a.get(i));
            char c1[] = s1.toCharArray();

            if (c1.length < 4) {
                for (int j = c1.length - 1; j >= 0; j--) {
                    finalc1[4 - 1 - j] = c1[j];
                }
            } else {
                finalc1 = c1;
            }

            i++;

            String s2 = Integer.toBinaryString(a.get(i));
            char c2[] = s2.toCharArray();

            if (c2.length < 4) {
                for (int j = c2.length - 1; j >= 0; j--) {
                    finalc2[4 - 1 - j] = c2[j];
                }
            } else {
                finalc2 = c2;
            }

        }

        //Cross over point = 2
        System.out.println("After crossover:");

        for (int i = 2; i < finalc1.length; i++) {
            char temp = finalc1[i];
            finalc1[i] = finalc2[i];
            finalc2[i] = temp;
        }

        for (int i = 0; i < finalc1.length; i++) {
            System.out.print(finalc1[i]);
        }

        System.out.println();

        for (int i = 0; i < finalc2.length; i++) {
            System.out.print(finalc2[i]);
        }

        System.out.println();

        //Mutation point = 3 and mutation rate = 12.5% ;
        if (finalc1[2] == '0') {
            finalc1[2] = '1';
        } else {
            finalc1[2] = '0';
        }

        if (finalc2[2] == '0') {
            finalc2[2] = '1';
        } else {
            finalc2[2] = '0';
        }

        System.out.println("After Mutation:");

        for (int i = 0; i < finalc1.length; i++) {
            System.out.print(finalc1[i]);
        }

        System.out.println();

        for (int i = 0; i < finalc2.length; i++) {
            System.out.print(finalc2[i]);
        }

        System.out.println();

        a.set(0, Integer.parseInt(String.valueOf(finalc1), 2));
        a.set(1, Integer.parseInt(String.valueOf(finalc2), 2));
        print();

        Collections.sort(a);
        System.out.println(a.get(a.size() - 1) + " will yield the maximum value");

    }

    public static void print() {
        System.out.println("a is " + "\t" + a);
        System.out.println("fx is " + "\t" + fx);
        System.out.println("pi is " + "\t" + probi);
        System.out.println("ei is " + "\t" + ei);
        System.out.println("ac is " + "\t" + ac);
        //System.out.println("The sum is "+ sum + ", the average is "+avg + " and the max is "+max);

    }

}


/*OUTPUT:
Enter the number of initial chromosomes
4
Enter the initial population
1
2
5
8
a is    [1, 2, 5, 8]
fx is   [1, 4, 25, 64]
pi is   [0.010638297872340425, 0.0425531914893617, 0.26595744680851063, 0.6808510638297872]
ei is   [0.043478260869565216, 0.17391304347826086, 1.0869565217391304, 2.782608695652174]
ac is   [0, 0, 1, 3]
a is    [5, 8, 8, 8]
fx is   [1, 4, 25, 64]
pi is   [0.010638297872340425, 0.0425531914893617, 0.26595744680851063, 0.6808510638297872]
ei is   [0.043478260869565216, 0.17391304347826086, 1.0869565217391304, 2.782608695652174]
ac is   [0, 0, 1, 3]
After crossover:
0100
1001
After Mutation:
0110
1011
a is    [6, 11, 8, 8]
fx is   [1, 4, 25, 64]
pi is   [0.010638297872340425, 0.0425531914893617, 0.26595744680851063, 0.6808510638297872]
ei is   [0.043478260869565216, 0.17391304347826086, 1.0869565217391304, 2.782608695652174]
ac is   [0, 0, 1, 3]
11 will yield the maximum value
*/