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package BasicPractice;

public class makePrimeLadder {

public static void main(String[] args) {

int n = 10;

display(makeLadder(n));

}

public static int[] makeLadder(int n) {

int[] ladder = new int[n + 1];

for (int i = 0; i <= n; i++) {

if (checkPrime(i)) {

ladder[i] = 1;

}

}

int first = 0, second = 0, lastfirst = 0, lastsecond = 0;

for (int i = 0; i <= n; i++) {

if (ladder[i] == 1) {

if (first == 0) {

first = i;

} else if (first > 0 && second == 0) {

second = i;

}

}

if (first > 0 && second > 0) {

break;

}

}

for (int i = n; i >= 0; i--) {

if (ladder[i] == 1) {

if (lastfirst == 0) {

lastfirst = i;

} else if (lastfirst > 0 && lastsecond == 0) {

lastsecond = i;

}

}

if (lastfirst > 0 && lastsecond > 0) {

break;

}

}

ladder[first] = lastfirst;

ladder[second] = lastsecond;

ladder[lastfirst] = first;

ladder[lastsecond] = second;

return ladder;

}

public static boolean checkPrime(int n) {

if (n < 2) {

return false;

}

for (int i = 2; i <= n / 2; i++) {

if (n % i == 0) {

return false;

}

}

return true;

}

public static void display(int[] list) {

for (int i = 0; i < list.length; i++) {

System.out.print(list[i] + " ");

}

System.out.println();

}

}