906.Super Palindrome

906.Super Palindrome(1st Math).java

class Solution {
    public int superpalindromesInRange(String L, String R) {
        Long l = (long)Math.sqrt(Long.parseLong(L));
        Long r = (long)Math.sqrt(Long.parseLong(R));
        int re = 0;
        for(int odd = 0;odd <= 1;odd++){
            long core = 1;
            long num = getP(core,odd == 0);
            while(num <= r){
                if(num >= l){
                   if(isP(num*num))re++; 
                }
                num = getP(++core,odd == 0);
            }
        }
        return re;
    }
    private boolean isP(long num){
        long n = num;
        long tmp = 0;
        while(num > 0){
            tmp = tmp *10 + num%10;
            num = num/10;
        }
        return tmp == n;
    }
    private long getP(long core,boolean isOdd){
        long re = core;
        if(isOdd){
            if(re < 10)return re;
            else re /= 10;
        }
        while(core > 0){
            re = re *10 +core%10;
            core /= 10;
        }
        return re;
    }
}

906.Super Palindrome(2nd String).java

class Solution {
    public int superpalindromesInRange(String L, String R) {
        Long l = Long.valueOf(L), r = Long.valueOf(R);
        int result = 0;
        for (long i = (long)Math.sqrt(l); i * i <= r;) {
            long p = nextP(i);
            if (p * p <= r && isP(p * p)) {
                result++;
            }
            i = p + 1;
        }
        return result;
    }
    
    private long nextP(long l) {
        String s = "" + l;
        int len = s.length();
        List<Long> cands = new LinkedList<>();
        cands.add((long)Math.pow(10, len) - 1);
        String half = s.substring(0, (len + 1) / 2);
        String nextHalf = "" + (Long.valueOf(half) + 1);
        String reverse = new StringBuilder(half.substring(0, len / 2)).reverse().toString();
        String nextReverse = new StringBuilder(nextHalf.substring(0, len / 2)).reverse().toString();
        cands.add(Long.valueOf(half + reverse));
        cands.add(Long.valueOf(nextHalf + nextReverse));
        long result = Long.MAX_VALUE;
        for (long i : cands) {
            if (i >= l) {
                result = Math.min(result, i);
            }
        }
        return result;
    }
    
    private boolean isP(long l) {
        String s = "" + l;
        int i = 0, j = s.length() - 1;
        while (i < j) {
            if (s.charAt(i++) != s.charAt(j--)) {
                return false;
            }
        }
        return true;
    }
}