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Link list algorithm to find pairs adding up to 10

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问题 Can you suggest an algorithm that find all pairs of nodes in a link list that add up to 10. I came up with the following. Algorithm: Compare each node, starting with the second node, with each node starting from the head node till the previous node (previous to the current node being compared) and report all such pairs. I think this algorithm should work however its certainly not the most efficient one having a complexity of O(n2). Can anyone hint at a solution which is more efficient

What category of combinatorial problems appear on the logic games section of the LSAT?

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问题 EDIT : See Solving "Who owns the Zebra" programmatically? for a similar class of problem There's a category of logic problem on the LSAT that goes like this: Seven consecutive time slots for a broadcast, numbered in chronological order I through 7, will be filled by six song tapes-G, H, L, O, P, S-and exactly one news tape. Each tape is to be assigned to a different time slot, and no tape is longer than any other tape. The broadcast is subject to the following restrictions: L must be played

How can I speed up my solution to this self-describing number puzzle? [closed]

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问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 7 years ago . I came across this puzzle from centerofmath.org via Twitter: There is a ten-digit number where the leftmost digit is also the number of zeros in the number, the second leftmost digit is the number of ones and so forth until the last digit (or rightmost digit) is the number of nines in that number. What is this

Why won't it remove from the set?

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问题 This bug took me a while to find... Consider this method: public void foo(Set<Object> set) { Object obj=set.iterator().next(); set.remove(obj) } I invoke the method with a non-empty hash set, but no element will be removed! Why would that be? 回答1: For a HashSet, this can occur if the object's hashCode changes after it has been added to the set. The HashSet.remove() method may then look in the wrong Hash bucket and fail to find it. This probably wouldn't happen if you did iterator.remove(),

Iterative Deepening A Star (IDA*) to solve n-puzzle (sliding puzzle) in Java

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问题 I've implemented a program able to solve the n-puzzle problem with A*. Since the space of the states is too big I cannot precompile it and I have to calculate the possible states at runtime. In this way A* works fine for a 3-puzzle, but for a 4-puzzle can take too long. Using Manhattan distance adjusted with linear conflicts, if the optimal solution requires around 25 moves is still fast, around 35 takes 10 seconds, for 40 takes 180 seconds. I haven't tried more yet. I think that's because I

Link list algorithm to find pairs adding up to 10

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Can you suggest an algorithm that find all pairs of nodes in a link list that add up to 10. I came up with the following. Algorithm: Compare each node, starting with the second node, with each node starting from the head node till the previous node (previous to the current node being compared) and report all such pairs. I think this algorithm should work however its certainly not the most efficient one having a complexity of O(n2). Can anyone hint at a solution which is more efficient (perhaps takes linear time). Additional or temporary nodes can be used by such a solution. If their range is

Placing words in table grid in word search puzzle?

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问题 I am trying to create a words search puzzle generated by script. The words should be placed horizontally, vertically or diagonally. I might need the option to set whether they are allowed to read only forward or backward. I have an array of words such as (apple, banana, grape, lemon, pear) which needs to be placed in the table. I have already created the table but I am stuck at how to place the words in the grid. I am looking for examples with some explanation. Please see my code below: var

How can I create a threshold for similar strings using Levenshtein distance and account for typos?

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问题 We recently encountered an interesting problem at work where we discovered duplicate user submitted data in our database. We realized that the Levenshtein distance between most of this data was simply the difference between the 2 strings in question. That indicates that if we simply add characters from one string into the other then we end up with the same string, and for most things this seems like the best way for us to account for items that are duplicate. We also want to account for typos

What category of combinatorial problems appear on the logic games section of the LSAT?

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EDIT : See Solving "Who owns the Zebra" programmatically? for a similar class of problem There's a category of logic problem on the LSAT that goes like this: Seven consecutive time slots for a broadcast, numbered in chronological order I through 7, will be filled by six song tapes-G, H, L, O, P, S-and exactly one news tape. Each tape is to be assigned to a different time slot, and no tape is longer than any other tape. The broadcast is subject to the following restrictions: L must be played immediately before O. The news tape must be played at some time after L. There must be exactly two time

Finding the largest positive int in an array by recursion

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问题 I decided to implement a very simple program recursively, to see how well Java handles recursion*, and came up a bit short. This is what I ended up writing: public class largestInIntArray { public static void main(String[] args) { // These three lines just set up an array of ints: int[] ints = new int[100]; java.util.Random r = new java.util.Random(); for(int i = 0; i < 100; i++) ints[i] = r.nextInt(); System.out.print("Normal:"+normal(ints,-1)+" Recursive:"+recursive(ints,-1)); } private