Think about Zuma Game. You have a row of balls on the table, colored red(R), yellow(Y), blue(B), green(G), and white(W). You also have several balls in your hand. Each time, you may choose a ball in your hand, and insert it into the row (including the leftmost place and rightmost place). Then, if there is […]

# Category: Java interview questions

## Number Complement – Leetcode

Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Note: The given integer is guaranteed to fit within the range of a 32-bit signed integer. You could assume no leading zero bit in the integer’s binary representation. Example 1:

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Input: 5 Output: 2 Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2. |

Example 2:

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Input: 1 Output: 0 Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0. |

[…]

## Max Consecutive Ones – Leetcode

Given a binary array, find the maximum number of consecutive 1s in this array. Example 1:

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Input: [1,1,0,1,1,1] Output: 3 Explanation: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s is 3. |

Note: The input array will only contain 0 and 1. The length of input array is a positive integer and will not exceed 10,000 Solution This is an easy to solve problem. We keep on counting the ones till a […]

## Construct the Rectangle Leetcode

Given a specific rectangular web page’s area, your job by now is to design a rectangular web page, whose length L and width W satisfy the following requirements:

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1. The area of the rectangular web page you designed must equal to the given target area. 2. The width W should not be larger than the length L, which means L >= W. 3. The difference between length L and width W should be as small as possible. |

You need to output the length L and the width W of the web page you designed in sequence. Example:

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Input: 4 Output: [2, 2] Explanation: The target area is 4, and all the possible ways to construct it are [1,4], [2,2], [4,1]. But according to requirement 2, [1,4] is illegal; according to requirement 3, [4,1] is not optimal compared to [2,2]. So the length L is 2, and the width W is 2. |

Note: The given area […]

## Binary Tree Paths

Problem Given a binary tree, return all root-to-leaf paths. Define a tree with left and right nodes

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package com.javagists.learn.interview.questions; // author javagists.com class TreeNode { TreeNode left, right; int val; TreeNode(int val) { this.val = val; left = right = null; } } |

Create Binary Tree and print path

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package com.javagists.learn.interview.questions; // author javagists.com public class BinaryTree { TreeNode root; void printAllPaths(TreeNode node) { int path[] = new int[50]; printPathsRecur(node, path, 0); } void printPathsRecur(TreeNode node, int path[], int pathLen) { if (node == null) { return; } path[pathLen] = node.val; pathLen++; if (node.left == null && node.right == null) { printArray(path, pathLen); } else { printPathsRecur(node.left, path, pathLen); printPathsRecur(node.right, path, pathLen); } } void printArray(int ints[], int len) { for (int i = 0; i < len; i++) { System.out.print(ints[i] + " " ); } System.out.println(""); } public static void main(String args[]) { BinaryTree tree = new BinaryTree(); tree.root = new TreeNode(3); tree.root.left = new TreeNode(4); tree.root.right = new TreeNode(5); tree.root.left.left = new TreeNode(6); tree.root.left.right = new TreeNode(9); tree.root.right.left = new TreeNode(2); tree.printAllPaths(tree.root); } } |