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47 lines
1.5 KiB
HTML
47 lines
1.5 KiB
HTML
<p>Given an array of integers <code>arr</code>, you are initially positioned at the first index of the array.</p>
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<p>In one step you can jump from index <code>i</code> to index:</p>
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<ul>
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<li><code>i + 1</code> where: <code>i + 1 < arr.length</code>.</li>
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<li><code>i - 1</code> where: <code>i - 1 >= 0</code>.</li>
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<li><code>j</code> where: <code>arr[i] == arr[j]</code> and <code>i != j</code>.</li>
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</ul>
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<p>Return <em>the minimum number of steps</em> to reach the <strong>last index</strong> of the array.</p>
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<p>Notice that you can not jump outside of the array at any time.</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> arr = [100,-23,-23,404,100,23,23,23,3,404]
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<strong>Output:</strong> 3
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<strong>Explanation:</strong> You need three jumps from index 0 --> 4 --> 3 --> 9. Note that index 9 is the last index of the array.
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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> arr = [7]
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<strong>Output:</strong> 0
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<strong>Explanation:</strong> Start index is the last index. You do not need to jump.
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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> arr = [7,6,9,6,9,6,9,7]
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<strong>Output:</strong> 1
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<strong>Explanation:</strong> You can jump directly from index 0 to index 7 which is last index of the array.
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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>1 <= arr.length <= 5 * 10<sup>4</sup></code></li>
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<li><code>-10<sup>8</sup> <= arr[i] <= 10<sup>8</sup></code></li>
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</ul>
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