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45 lines
1.9 KiB
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45 lines
1.9 KiB
HTML
<p>You are given an integer array <code>target</code>. You have an integer array <code>initial</code> of the same size as <code>target</code> with all elements initially zeros.</p>
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<p>In one operation you can choose <strong>any</strong> subarray from <code>initial</code> and increment each value by one.</p>
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<p>Return <em>the minimum number of operations to form a </em><code>target</code><em> array from </em><code>initial</code>.</p>
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<p>The test cases are generated so that the answer fits in a 32-bit integer.</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> target = [1,2,3,2,1]
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<strong>Output:</strong> 3
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<strong>Explanation:</strong> We need at least 3 operations to form the target array from the initial array.
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[<strong><u>0,0,0,0,0</u></strong>] increment 1 from index 0 to 4 (inclusive).
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[1,<strong><u>1,1,1</u></strong>,1] increment 1 from index 1 to 3 (inclusive).
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[1,2,<strong><u>2</u></strong>,2,1] increment 1 at index 2.
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[1,2,3,2,1] target array is formed.
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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> target = [3,1,1,2]
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<strong>Output:</strong> 4
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<strong>Explanation:</strong> [<strong><u>0,0,0,0</u></strong>] -> [1,1,1,<strong><u>1</u></strong>] -> [<strong><u>1</u></strong>,1,1,2] -> [<strong><u>2</u></strong>,1,1,2] -> [3,1,1,2]
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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> target = [3,1,5,4,2]
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<strong>Output:</strong> 7
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<strong>Explanation:</strong> [<strong><u>0,0,0,0,0</u></strong>] -> [<strong><u>1</u></strong>,1,1,1,1] -> [<strong><u>2</u></strong>,1,1,1,1] -> [3,1,<strong><u>1,1,1</u></strong>] -> [3,1,<strong><u>2,2</u></strong>,2] -> [3,1,<strong><u>3,3</u></strong>,2] -> [3,1,<strong><u>4</u></strong>,4,2] -> [3,1,5,4,2].
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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 <= target.length <= 10<sup>5</sup></code></li>
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<li><code>1 <= target[i] <= 10<sup>5</sup></code></li>
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</ul>
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