import java.util.*;

public class Solution {

public List<String> findMissingRanges(int[] vals, int start, int end) {

ArrayList<String> ret = new ArrayList<String>();

String first = validRange(start - 1, vals[0]);

if (first != null) ret.add(first);

for (int i = 1; i < vals.length; ++i) {

String curr = validRange(vals[i - 1], vals[i]);

if (curr != null) ret.add(curr);

}

String last = validRange(vals[vals.length - 1], end + 1);

if (last != null) ret.add(last);

return ret;

}

public String validRange(int a, int b) {

if (b - a > 1) {

int left = a + 1;

int right = b - 1;

if (left == right) {

return String.format("%d", left);

} else {

return String.format("%d->%d", left, right);

}

} else {

return null;

}

}

public static void main(String[] args) {

Solution s = new Solution();

List<String> sa = s.findMissingRanges(new int[] {0, 1, 3, 50, 75}, 0, 99);

for (String str : sa) {

System.out.println(str);

}

}

}