<p>An attendance record for a student can be represented as a string where each character signifies whether the student was absent, late, or present on that day. The record only contains the following three characters:</p>

<ul>
	<li><code>&#39;A&#39;</code>: Absent.</li>
	<li><code>&#39;L&#39;</code>: Late.</li>
	<li><code>&#39;P&#39;</code>: Present.</li>
</ul>

<p>Any student is eligible for an attendance award if they meet <strong>both</strong> of the following criteria:</p>

<ul>
	<li>The student was absent (<code>&#39;A&#39;</code>) for <strong>strictly</strong> fewer than 2 days <strong>total</strong>.</li>
	<li>The student was <strong>never</strong> late (<code>&#39;L&#39;</code>) for 3 or more <strong>consecutive</strong> days.</li>
</ul>

<p>Given an integer <code>n</code>, return <em>the <strong>number</strong> of possible attendance records of length</em> <code>n</code><em> that make a student eligible for an attendance award. The answer may be very large, so return it <strong>modulo</strong> </em><code>10<sup>9</sup> + 7</code>.</p>

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

<pre>
<strong>Input:</strong> n = 2
<strong>Output:</strong> 8
<strong>Explanation:</strong> There are 8 records with length 2 that are eligible for an award:
&quot;PP&quot;, &quot;AP&quot;, &quot;PA&quot;, &quot;LP&quot;, &quot;PL&quot;, &quot;AL&quot;, &quot;LA&quot;, &quot;LL&quot;
Only &quot;AA&quot; is not eligible because there are 2 absences (there need to be fewer than 2).
</pre>

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

<pre>
<strong>Input:</strong> n = 1
<strong>Output:</strong> 3
</pre>

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

<pre>
<strong>Input:</strong> n = 10101
<strong>Output:</strong> 183236316
</pre>

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

<ul>
	<li><code>1 &lt;= n &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    int mod=1e9+7;
    int populatePLArr(vector<vector<long long int>> &plarr,int i,int countOfConsecutiveL){
        if(i<0)
            return 1;
        long long int nextIsP=0, nextIsL=0;
        if(plarr[i][countOfConsecutiveL]!=-1)
            return plarr[i][countOfConsecutiveL];
        nextIsP = populatePLArr(plarr,i-1,0)%mod;
        if(countOfConsecutiveL<2){
            nextIsL = populatePLArr(plarr,i-1,countOfConsecutiveL+1)%mod;
        }
        
        return plarr[i][countOfConsecutiveL] = nextIsP+nextIsL;
    }
    int checkRecord(int n) {
        int MOD = 1e9 + 7;
        vector<vector<long long int>> plarr(n,vector<long long int>(3,-1));
        
        if(n==1){
            return 3;
        }else if(n==2){
            return 8;
        }
        else{
            populatePLArr(plarr,n-1,0);
            long long int ans=(plarr[n-1][0])%MOD;
            for(int i=0;i<n;i++){
                // for(int j=0;j<3;j++){
                //     cout<<plarr[i][j]<<" ";
                // }cout<<endl;
                if(i==0 || i==n-1){
                    ans = (ans%MOD + plarr[n-2][0]%MOD)%MOD;
                }else{
                    ans = (ans%MOD +(long long int)( (plarr[n-2-i][0]%MOD) * (plarr[i-1][0]%MOD))%MOD)%MOD;
                }
            }
            return ans;
        }
        return 0;
    }
};
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