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40 lines
1.1 KiB
HTML
40 lines
1.1 KiB
HTML
<p>Given an array of integers <code>arr</code>, return <em>the number of subarrays with an <strong>odd</strong> sum</em>.</p>
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<p>Since the answer can be very large, return it modulo <code>10<sup>9</sup> + 7</code>.</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 = [1,3,5]
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<strong>Output:</strong> 4
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<strong>Explanation:</strong> All subarrays are [[1],[1,3],[1,3,5],[3],[3,5],[5]]
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All sub-arrays sum are [1,4,9,3,8,5].
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Odd sums are [1,9,3,5] so the answer is 4.
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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 = [2,4,6]
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<strong>Output:</strong> 0
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<strong>Explanation:</strong> All subarrays are [[2],[2,4],[2,4,6],[4],[4,6],[6]]
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All sub-arrays sum are [2,6,12,4,10,6].
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All sub-arrays have even sum and the answer is 0.
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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 = [1,2,3,4,5,6,7]
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<strong>Output:</strong> 16
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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 <= 10<sup>5</sup></code></li>
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<li><code>1 <= arr[i] <= 100</code></li>
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</ul>
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