Cacher is the code snippet organizer for pro developers

public class Solution {
    private int compare(String s1, String s2) {
        if (s1.length() < s2.length()) return -1;
        else if (s1.length() > s2.length()) return 1;
        for (int i = 0; i < Math.min(s1.length(), s2.length()); i++) {
            if (s1.charAt(i) < s2.charAt(i)) return -1;
            else if (s1.charAt(i) > s2.charAt(i)) return 1;
        }
        return 0;
    }
    private int count;
    private final char[] pairs = {'0', '0', '1', '1', '6', '9', '8', '8', '9', '6'};
    private void helper(char[] nums, int start, int end, String low, String high, boolean lowerlimit, boolean upperlimit) {
        if (start > end) {
            String s = new String(nums);
            if ((!lowerlimit || compare(s, low) >= 0) && (!upperlimit || compare(s, high) <= 0)) count++;
            return;
        }
        for (int i = 0; i < 10; i += 2) {
            if (start == end && pairs[i] != pairs[i+1]) continue;
            nums[start] = pairs[i];
            nums[end] = pairs[i+1];
            if (start == 0 && nums[start] == '0' && nums.length > 1) continue;
            if (upperlimit && compare(new String(nums, 0, start+1), high.substring(0, start+1)) > 0) break;
            if (lowerlimit && compare(new String(nums, 0, start+1), low.substring(0, start+1)) < 0) continue;
            helper(nums, start+1, end-1, low, high, lowerlimit, upperlimit);
        }
    }
    public int strobogrammaticInRange(String low, String high) {
        if (compare(low, high) > 0) return 0;
        int n = low.length(), m = high.length(), result = 0;
        count = 0;
        if (m == n) {
            helper(new char[m], 0, m-1, low, high, true, true);
            result += count;
        } else {
            helper(new char[n], 0, n-1, low, high, true, false);
            result += count;
            count = 0;
            helper(new char[m], 0, m-1, low, high, false, true);
            result += count;
        }
        int even = 1, odd = 3;
        for (int i = 2; i < m; i++) {
            if (i > n && i < m) result += i%2 == 0 ? even*4 : odd*4;
            if (i%2 ==0) even = even*5;
            else odd = odd*5;
        }
        return result;
    }
}

public class Solution {
    public int strobogrammaticInRange(String low, String high) {
        int res=0;
        if(low.length()>high.length()) return 0;
        for (int i = low.length(); i <high.length() ; i++) {
            res+=strbgWithDigits(i, false);
        }
        res+=strbgWithSameDigitsBelow(high, false);
        res-=strbgWithSameDigitsBelow(low, false);
        if(isStb(low)) res++;
        return res;
    }

    private boolean isStb(String low) {
        if(low.length()==0) return true;
        for (int i = 0; i <= low.length()/2; i++) {
            if(!isPair(low.charAt(i),low.charAt(low.length()-i-1))) return false;
        }
        return true;
    }

    private boolean isPair(char c, char c1) {
        if(c=='1') return c1=='1';
        if(c=='0') return c1=='0';
        if(c=='8') return c1=='8';
        if(c=='6') return c1=='9';
        if(c=='9') return c1=='6';
        return false;
    }

    private int strbgWithSameDigitsBelow(String num, boolean can0Initial) {
        int res=0;
        if(num.length()==0){
            return 1;
        }
        if(num.length()==1) {
            int temp=1;
            if(num.charAt(0)>='1') temp++;
            if(num.charAt(0)>='8') temp++;
            return temp;
        }
        if(can0Initial && num.charAt(0)>'0') {
            res+=strbgWithDigits(num.length()-2,true);
        }
        if(num.charAt(0)>'1') {
            res+=strbgWithDigits(num.length()-2,true);
        }
        if(num.charAt(0)>'6') {
            res+=strbgWithDigits(num.length()-2,true);
        }
        if(num.charAt(0)>'8'){  //==9
            res+=strbgWithDigits(num.length()-2,true);
            res+=strbgWithSameDigitsBelow(num.substring(1,num.length()-1),true);
            if(isStb(num.substring(1,num.length()-1)) && num.charAt(num.length()-1)<'6') {
                res--;
            }
        }
        if(num.charAt(0)=='1'||num.charAt(0)=='8') {
            res+=strbgWithSameDigitsBelow(num.substring(1,num.length()-1),true);
            if(isStb(num.substring(1,num.length()-1)) && num.charAt(num.length()-1)<num.charAt(0)) {
                res--;
            }
        }
        if(num.charAt(0)=='6') {
            res+=strbgWithSameDigitsBelow(num.substring(1,num.length()-1),true);
            if(isStb(num.substring(1,num.length()-1)) && num.charAt(num.length()-1)<'9') {
                res--;
            }
        }
        if(num.charAt(0)=='0'&& can0Initial) {
            res+=strbgWithSameDigitsBelow(num.substring(1,num.length()-1),true);
        }

        return res;
    }

    private int strbgWithDigits(int d, boolean can0Initial) {
        if(d<=0) return 1;
        if(d==1) return 3;
        int res=4;
        if(can0Initial) {
            res=5;
        }
        for (int i = 1; i <d-1-i ; i++) {
            res*=5;
        }
        if(d%2==1) res*=3;
        return res;
    }
}

public class Solution {
    private static final char[][] pairs = {{'0', '0'}, {'1', '1'}, {'6', '9'}, {'8', '8'}, {'9', '6'}};

    public int strobogrammaticInRange(String low, String high) {
        int[] count = {0};
        for (int len = low.length(); len <= high.length(); len++) {
            char[] c = new char[len];
            dfs(low, high, c, 0, len - 1, count);
        }
        return count[0];
    }

    public void dfs(String low, String high , char[] c, int left, int right, int[] count) {
        if (left > right) {
            String s = new String(c);
            if ((s.length() == low.length() && s.compareTo(low) < 0) || 
                (s.length() == high.length() && s.compareTo(high) > 0)) {
                return;
            }
            count[0]++;
            return;
        }
        for (char[] p : pairs) {
            c[left] = p[0];
            c[right] = p[1];
            if (c.length != 1 && c[0] == '0') {
                continue;
            }
            if (left == right && p[0] != p[1]) {
                continue;
            }
            dfs(low, high, c, left + 1, right - 1, count);
        }
    }
}