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55 lines
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55 lines
2.4 KiB
HTML
<p>You are given a <strong>0-indexed</strong> integer array <code>nums</code> containing <strong>distinct</strong> numbers, an integer <code>start</code>, and an integer <code>goal</code>. There is an integer <code>x</code> that is initially set to <code>start</code>, and you want to perform operations on <code>x</code> such that it is converted to <code>goal</code>. You can perform the following operation repeatedly on the number <code>x</code>:</p>
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<p>If <code>0 <= x <= 1000</code>, then for any index <code>i</code> in the array (<code>0 <= i < nums.length</code>), you can set <code>x</code> to any of the following:</p>
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<ul>
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<li><code>x + nums[i]</code></li>
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<li><code>x - nums[i]</code></li>
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<li><code>x ^ nums[i]</code> (bitwise-XOR)</li>
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</ul>
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<p>Note that you can use each <code>nums[i]</code> any number of times in any order. Operations that set <code>x</code> to be out of the range <code>0 <= x <= 1000</code> are valid, but no more operations can be done afterward.</p>
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<p>Return <em>the <strong>minimum</strong> number of operations needed to convert </em><code>x = start</code><em> into </em><code>goal</code><em>, and </em><code>-1</code><em> if it is not possible</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> nums = [2,4,12], start = 2, goal = 12
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> We can go from 2 → 14 → 12 with the following 2 operations.
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- 2 + 12 = 14
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- 14 - 2 = 12
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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> nums = [3,5,7], start = 0, goal = -4
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<strong>Output:</strong> 2
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<strong>Explanation:</strong> We can go from 0 → 3 → -4 with the following 2 operations.
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- 0 + 3 = 3
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- 3 - 7 = -4
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Note that the last operation sets x out of the range 0 <= x <= 1000, which is valid.
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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> nums = [2,8,16], start = 0, goal = 1
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<strong>Output:</strong> -1
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<strong>Explanation:</strong> There is no way to convert 0 into 1.
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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 <= nums.length <= 1000</code></li>
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<li><code>-10<sup>9</sup> <= nums[i], goal <= 10<sup>9</sup></code></li>
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<li><code>0 <= start <= 1000</code></li>
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<li><code>start != goal</code></li>
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<li>All the integers in <code>nums</code> are distinct.</li>
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</ul>
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