<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) {
        long long arr[50000]{};
        for(int i = 0; i< 46341; i++){
            arr[i] = i*i;
        }
        int r = pow(c,0.5);
        int l = 0;
        while(l<r){
            if(arr[l]+arr[r] == c)return true;
            if(arr[l]+arr[r] < c){
                l++;
            }
            else{
                r--;
            }
        }
        for(int i=0 ; arr[i]<<1 <= c ;i++){
            if(arr[i]<<1 == c)return true;
        }
        return false;
    }
};
auto init = []() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
return 0;
}();
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