<p>Given a non-negative integer <code>c</code>, decide whether there&#39;re two integers <code>a</code> and <code>b</code> such that <code>a<sup>2</sup> + b<sup>2</sup> = c</code>.</p>

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

<pre>
<strong>Input:</strong> c = 5
<strong>Output:</strong> true
<strong>Explanation:</strong> 1 * 1 + 2 * 2 = 5
</pre>

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

<pre>
<strong>Input:</strong> c = 3
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>0 &lt;= c &lt;= 2<sup>31</sup> - 1</code></li>
</ul>

class Solution {
public:
    bool judgeSquareSum(int c) {
        vector<long>v;
        for(int i=0;i<=sqrt(c);i++){
              long mul=i*i;
                v.push_back((mul));
            
        }
        sort(v.begin(),v.end());
        int i=0;
        int j=v.size()-1;
        while(i<=j){
            long sum=v[i]+v[j];
            if(sum==c){
                return true;
            }
            else if(sum>c){
                j--;
            }
            else {
                i++;
            }
        }
     return false;

    
    // int left=0;
    // long right=(long)sqrt(c);
    // while(left<=right){
    //     long mul=left*left + right*right;
    //     if(mul==c){
    //         return true;
    //     }
    //     else if(mul>c){
    //         right--;
    //     }
    //     else if(mul<c){
    //         left++;
    //     }
    // }
    // return false;
    }
};
31000