<p>Given two integers <code>left</code> and <code>right</code> that represent the range <code>[left, right]</code>, return <em>the bitwise AND of all numbers in this range, inclusive</em>.</p>

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

<pre>
<strong>Input:</strong> left = 5, right = 7
<strong>Output:</strong> 4
</pre>

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

<pre>
<strong>Input:</strong> left = 0, right = 0
<strong>Output:</strong> 0
</pre>

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

<pre>
<strong>Input:</strong> left = 1, right = 2147483647
<strong>Output:</strong> 0
</pre>

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

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

class Solution {
public:
    int rangeBitwiseAnd(int left, int right) {
        int res = 0;
        int cnt = 0; for(; left >= (1ll<<cnt); cnt++){}
        if(1ll<<cnt <= right) return 0;
        if(left==right) return left;
        
        res += 1ll<<(--cnt);
        left -= 1ll<<(cnt); right -= 1ll<<cnt;
        return res + rangeBitwiseAnd(left, right);
    }
};
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