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47 lines
2.8 KiB
HTML
47 lines
2.8 KiB
HTML
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<p>Design a stack which supports the following operations.</p>
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<p>Implement the <code>CustomStack</code> class:</p>
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<ul>
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<li><code>CustomStack(int maxSize)</code> Initializes the object with <code>maxSize</code> which is the maximum number of elements in the stack or do nothing if the stack reached the <code>maxSize</code>.</li>
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<li><code>void push(int x)</code> Adds <code>x</code> to the top of the stack if the stack hasn't reached the <code>maxSize</code>.</li>
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<li><code>int pop()</code> Pops and returns the top of stack or <strong>-1</strong> if the stack is empty.</li>
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<li><code>void inc(int k, int val)</code> Increments the bottom <code>k</code> elements of the stack by <code>val</code>. If there are less than <code>k</code> elements in the stack, just increment all the elements in the stack.</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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["CustomStack","push","push","pop","push","push","push","increment","increment","pop","pop","pop","pop"]
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[[3],[1],[2],[],[2],[3],[4],[5,100],[2,100],[],[],[],[]]
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<strong>Output</strong>
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[null,null,null,2,null,null,null,null,null,103,202,201,-1]
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<strong>Explanation</strong>
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CustomStack customStack = new CustomStack(3); // Stack is Empty []
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customStack.push(1); // stack becomes [1]
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customStack.push(2); // stack becomes [1, 2]
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customStack.pop(); // return 2 --> Return top of the stack 2, stack becomes [1]
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customStack.push(2); // stack becomes [1, 2]
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customStack.push(3); // stack becomes [1, 2, 3]
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customStack.push(4); // stack still [1, 2, 3], Don't add another elements as size is 4
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customStack.increment(5, 100); // stack becomes [101, 102, 103]
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customStack.increment(2, 100); // stack becomes [201, 202, 103]
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customStack.pop(); // return 103 --> Return top of the stack 103, stack becomes [201, 202]
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customStack.pop(); // return 202 --> Return top of the stack 102, stack becomes [201]
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customStack.pop(); // return 201 --> Return top of the stack 101, stack becomes []
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customStack.pop(); // return -1 --> Stack is empty return -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 <= maxSize <= 1000</code></li>
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<li><code>1 <= x <= 1000</code></li>
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<li><code>1 <= k <= 1000</code></li>
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<li><code>0 <= val <= 100</code></li>
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<li>At most <code>1000</code> calls will be made to each method of <code>increment</code>, <code>push</code> and <code>pop</code> each separately.</li>
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</ul>
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