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50 lines
1.7 KiB
HTML
50 lines
1.7 KiB
HTML
<p>There are <code>n</code> persons on a social media website. You are given an integer array <code>ages</code> where <code>ages[i]</code> is the age of the <code>i<sup>th</sup></code> person.</p>
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<p>A Person <code>x</code> will not send a friend request to a person <code>y</code> (<code>x != y</code>) if any of the following conditions is true:</p>
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<ul>
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<li><code>age[y] <= 0.5 * age[x] + 7</code></li>
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<li><code>age[y] > age[x]</code></li>
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<li><code>age[y] > 100 && age[x] < 100</code></li>
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</ul>
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<p>Otherwise, <code>x</code> will send a friend request to <code>y</code>.</p>
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<p>Note that if <code>x</code> sends a request to <code>y</code>, <code>y</code> will not necessarily send a request to <code>x</code>. Also, a person will not send a friend request to themself.</p>
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<p>Return <em>the total number of friend requests made</em>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> ages = [16,16]
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> 2 people friend request each other.
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> ages = [16,17,18]
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> Friend requests are made 17 -> 16, 18 -> 17.
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</pre>
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<p><strong>Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> ages = [20,30,100,110,120]
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<strong>Output:</strong> 3
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<strong>Explanation:</strong> Friend requests are made 110 -> 100, 120 -> 110, 120 -> 100.
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>n == ages.length</code></li>
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<li><code>1 <= n <= 2 * 10<sup>4</sup></code></li>
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<li><code>1 <= ages[i] <= 120</code></li>
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</ul>
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