analysis of algorithms book

In various data mining algorithms, association rule mining is an important one, especially influenced by basket analysis. association rules are applied to many real businesses, this article makes a small Summary of association rule mining. First, like clustering algorithms, association rule mining is an unsupervised learning method that describes the patterns of

algorithm complexity analysis assuming worst case, the loop is found after X times , then: 2^x=n; X=logn (if not written in the algorithm, the log default base is 2) the number and depth of recursion is log2 N, each time the required secondary space is a constant level: time complexity: O (log2 N), spatial complexity: O (log2n). 7. Extended-----to seek 1+2+3+...+n without cyclic method and recursive method (think of a solution with the complexity of

consider using the method of forward and reverse two-pass bubbling in each order to get two final values at a time (maximum and minimum), thus reducing the number of sort passes by almost half.The improved algorithm is:The three algorithms run at the following times:By running the results you can see that the complexity of the time is lower, and it takes much shorter. You can try it yourself, it is best to run the three

that may be ordered in the program are simple types, and actually when applied, it is possible to sort the array of a complex type (custom type). The sorted key value is just one attribute of this element, and for a simple type, the numeric value is its full meaning, even if the exchange is not different. However, in the case of complex types, the exchange of words may cause an exchange of elements that should not otherwise be exchanged. For example: A "student" array, in order to sort by age,

after a deep understanding, you will find that this function does the same work as the above function. T is because this function is not so obvious and the code is difficult. Check. we did not use a good variable name, resulting in poor readability and declared variables that do not need to be declared. def foo (tom): fred = 0 for bill in range (1, tom + 1): barney = bill fred = fred + barney return fredprint (foo (10 )) which code is better. the answer to the question depends on your criteria.

Although the NoSQL movement does not bring fundamental technological changes to distributed data processing, it still leads to a deluge of research and practice on protocols and algorithms. In this article, I will make some systematic descriptions of the distributed features of the NoSQL database. The scalability of the system is the main reason to drive the development of the NoSQL movement, including distributed system coordination, failover, resou

is pushed forward step by step until all the Code involved in the calculation is analyzed. The core algorithm found, the analysis algorithm is relatively simple, but involves a lot of SSE extended instructions, the use of xmm0-xmm7 registers, and OD does not show the content of these registers, analysis is very painful, although windbg can display the content of these registers, it is equally painful to us

: partition (key, which sorts the child array a [P. R] in place) C ++ implementation: // * Chapter 7 quick sorting of algorithms * // # include Quick performance analysis: When the data volume is small, it is about a small sequence of 10 or more elements. The advantage of fast sorting is not obvious, or even slower than insertion sorting. However, once there is a large amount of data, its advantages wi

to sort the array of a complex type (custom type) . the sorted key value is just one attribute of this element, and for a simple type, the numeric value is its full meaning, even if the exchange is not different. However, in the case of complex types, the exchange of words may cause an exchange of elements that should not otherwise be exchanged. For example: A "student" array, in order to sort by age, "student" This object not only contains "age", there are many other attributes. if the origina

algorithms: 1. void get_next (SString T, int next []) 2 .{ 3. // evaluate the next function value of the pattern string T and store it to the array next 4. I = 1; next [1] = 0; j = 0; 5. while (I 6 .{ 7. if (j = 0 | T [I] = T [j]) 8 .{ 9. ++ I; ++ j; 10. if (T [I]! = T [j]) 11. next [I] = j; 12. else 13. next [I] = next [j]; 14 .} 15. else 16 .{ 17. j = next [j]; 18 .} 19 .} 20 .} 4. Algorithm Implementation The difficulty of the KMP algorithm is t

or equal to its 2 child nodes. In a sequence of n, the process of heap sequencing is to select the largest (large top heap) or the smallest (small top heap) from the beginning of N/2 and its child nodes by a total of 3 values, and the choice between the 3 elements will of course not destabilize. But when for n/2-1, N/2-2, ... 1 When these parent nodes select an element, the stability is broken. It is possible that the N/2 of the parent node Exchange passes the latter element, while the n/2-1 pa

In-depth analysis of distributed algorithms for NoSQL Databases System scalability is the main reason for promoting the development of NoSQL, including distributed system coordination, failover, resource management and many other features. In this case, NoSQL sounds like a big basket, and everything can be inserted. Although the NoSQL movement has not brought about fundamental technological changes to dist

stability is broken. It is possible that the N/2 of the parent node Exchange passes the latter element, while the n/2-1 parent node does not exchange the subsequent same element, then the stability between the 2 identical elements is destroyed. Therefore, heap sorting is not a stable sorting algorithm . Third, the complexity ofIn short, use the following table to indicate Sorting method Complexity of Time Complexity of space Stability Aver

found that the problem should be String.charat () above, the code is as follows:public char charAt (int index) { if (Index There are two judgments that are very time-consuming, and we change to the following codeif (strs.length==0) return ""; String prefix =strs[0];for (int i = 1;ibecomes the 2ms, sure enough the problem is here, if we do not use the ToCharArray () method should be 1ms, which shows that our ideas and algorithms