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50 lines
3.5 KiB
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50 lines
3.5 KiB
HTML
<p>A <strong>Bitset</strong> is a data structure that compactly stores bits.</p>
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<p>Implement the <code>Bitset</code> class:</p>
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<ul>
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<li><code>Bitset(int size)</code> Initializes the Bitset with <code>size</code> bits, all of which are <code>0</code>.</li>
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<li><code>void fix(int idx)</code> Updates the value of the bit at the index <code>idx</code> to <code>1</code>. If the value was already <code>1</code>, no change occurs.</li>
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<li><code>void unfix(int idx)</code> Updates the value of the bit at the index <code>idx</code> to <code>0</code>. If the value was already <code>0</code>, no change occurs.</li>
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<li><code>void flip()</code> Flips the values of each bit in the Bitset. In other words, all bits with value <code>0</code> will now have value <code>1</code> and vice versa.</li>
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<li><code>boolean all()</code> Checks if the value of <strong>each</strong> bit in the Bitset is <code>1</code>. Returns <code>true</code> if it satisfies the condition, <code>false</code> otherwise.</li>
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<li><code>boolean one()</code> Checks if there is <strong>at least one</strong> bit in the Bitset with value <code>1</code>. Returns <code>true</code> if it satisfies the condition, <code>false</code> otherwise.</li>
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<li><code>int count()</code> Returns the <strong>total number</strong> of bits in the Bitset which have value <code>1</code>.</li>
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<li><code>String toString()</code> Returns the current composition of the Bitset. Note that in the resultant string, the character at the <code>i<sup>th</sup></code> index should coincide with the value at the <code>i<sup>th</sup></code> bit of the Bitset.</li>
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</ul>
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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>
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["Bitset", "fix", "fix", "flip", "all", "unfix", "flip", "one", "unfix", "count", "toString"]
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[[5], [3], [1], [], [], [0], [], [], [0], [], []]
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<strong>Output</strong>
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[null, null, null, null, false, null, null, true, null, 2, "01010"]
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<strong>Explanation</strong>
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Bitset bs = new Bitset(5); // bitset = "00000".
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bs.fix(3); // the value at idx = 3 is updated to 1, so bitset = "00010".
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bs.fix(1); // the value at idx = 1 is updated to 1, so bitset = "01010".
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bs.flip(); // the value of each bit is flipped, so bitset = "10101".
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bs.all(); // return False, as not all values of the bitset are 1.
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bs.unfix(0); // the value at idx = 0 is updated to 0, so bitset = "00101".
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bs.flip(); // the value of each bit is flipped, so bitset = "11010".
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bs.one(); // return True, as there is at least 1 index with value 1.
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bs.unfix(0); // the value at idx = 0 is updated to 0, so bitset = "01010".
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bs.count(); // return 2, as there are 2 bits with value 1.
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bs.toString(); // return "01010", which is the composition of bitset.
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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 <= size <= 10<sup>5</sup></code></li>
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<li><code>0 <= idx <= size - 1</code></li>
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<li>At most <code>10<sup>5</sup></code> calls will be made <strong>in total</strong> to <code>fix</code>, <code>unfix</code>, <code>flip</code>, <code>all</code>, <code>one</code>, <code>count</code>, and <code>toString</code>.</li>
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<li>At least one call will be made to <code>all</code>, <code>one</code>, <code>count</code>, or <code>toString</code>.</li>
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<li>At most <code>5</code> calls will be made to <code>toString</code>.</li>
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</ul>
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