<p>An integer <code>x</code> is a <strong>good</strong> if after rotating each digit individually by 180 degrees, we get a valid number that is different from <code>x</code>. Each digit must be rotated - we cannot choose to leave it alone.</p>

<p>A number is valid if each digit remains a digit after rotation. For example:</p>

<ul>
	<li><code>0</code>, <code>1</code>, and <code>8</code> rotate to themselves,</li>
	<li><code>2</code> and <code>5</code> rotate to each other (in this case they are rotated in a different direction, in other words, <code>2</code> or <code>5</code> gets mirrored),</li>
	<li><code>6</code> and <code>9</code> rotate to each other, and</li>
	<li>the rest of the numbers do not rotate to any other number and become invalid.</li>
</ul>

<p>Given an integer <code>n</code>, return <em>the number of <strong>good</strong> integers in the range </em><code>[1, n]</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 10
<strong>Output:</strong> 4
<strong>Explanation:</strong> There are four good numbers in the range [1, 10] : 2, 5, 6, 9.
Note that 1 and 10 are not good numbers, since they remain unchanged after rotating.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 1
<strong>Output:</strong> 0
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> n = 2
<strong>Output:</strong> 1
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
    
public:
    int rotatedDigits(int n) {
        int count=0;
        static int dp[10001];
        for(int i=1;i<=n;i++){
            if(dp[i] != 0){
                if(dp[i]==1)count++;
                continue;
            }
            string s=to_string(i);
            bool flag=true;
            for(int j=0;j<s.size();j++){
                if(s[j]=='2')s[j]='5';
                else if(s[j]=='5')s[j]='2';
                else if(s[j]=='6')s[j]='9';
                else if(s[j]=='9')s[j]='6';
                else if(s[j]=='3'||s[j]=='4'||s[j]=='7'){
                    flag=false;
                    break;
                }
                
            }
            int b=stoi(s);
                cout<<b<<endl;
                if(flag && b!=i){
                    dp[i]=1;
                    count++;
                }
                else{
                    dp[i]=-1;
                }
        }
        return count;
    }
};
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