摘要： http://www.geeksforgeeks.org/check-for-children-sum-property-in-a-binary-tree/ 1 #include 2 #include 3 #include 4 #include 5 #include 6 using namespace std; 7 8 struct node { 9 int data;10 struct node *left, *right;11 node() : data(0), left(NULL), right(NULL) { }12 node(int d) ... 阅读全文

摘要： http://www.geeksforgeeks.org/level-order-traversal-in-spiral-form/ 1 #include 2 #include 3 #include 4 #include 5 #include 6 using namespace std; 7 8 struct node { 9 int data;10 struct node *left, *right;11 node() : data(0), left(NULL), right(NULL) { }12 node(int d) : data(d), l... 阅读全文

摘要： 1 struct node { 2 int val; 3 node *left; 4 node *right; 5 node *parent; 6 node() : val(0), left(NULL), right(NULL) { } 7 node(int v) : val(v), left(NULL), right(NULL) { } 8 }; 9 10 node* insert(int n, node *root) {11 if (root == NULL) {12 root = new node(n);13 ... 阅读全文

摘要： 1. 一个数的从右起第p1位和第p2位swap n位 1 unsigned int swapBits(unsigned int x, unsigned int p1, unsigned int p2, unsigned int n) { 2 unsigned int set1 = (x >> p1) & ((1 > p2) & ((1 > (sizeof(int) * 8 - 1)));3 }also can use division4. count bit set in an integer1 int countsetbits(int x) {2 in 阅读全文

摘要： kmp算法：用一个数组保存了上一个需要开始搜索的index，比如AAACAAA就是0， 1， 2， 0， 1， 2， 3， ABCABC就是0， 0， 0， 1， 2， 3，复杂度O（M+N） 1 #include 2 #include 3 #include 4 #include 5 #include 6 7 using namespace std; 8 9 int main()10 {11 string pattern = "ABCABC";12 string s = "ABCABCABCABCBCABC";13 vector lps(pattern. 阅读全文

摘要： 1. Longest Increasing Subsequence (LIS) problemunsorted array, calculate out the maximum length of subsequence with non-decreasing order.lis[i] = lis[... 阅读全文

摘要： inversion就是逆序对题目：现给出一个数列，求该数列中的逆序对数（逆序数）。本节给出三种方法：方法一是最直接的暴力方法；方法二是基于归并分治的思想；方法三是基于线段树的。【解法一】暴力方法最直接，也最容易想到，两层for循环就可以算出来逆序数：每遇到一个元素回头遍历寻找比其大的元素个数即可，当然向后寻找比其小的元素个数也可以，复杂度为O(n^2)，代码：123456789101112int sum = 0;for(int i = 0; i arr[j]){++sum;}}}return sum;【解法二】这种方法最初见于《算法导论》，这里先附上《算法导论》2-4关于逆序对的几点讨论：1. 阅读全文

摘要： q.1:Find the titles of all movies directed by Steven Spielberg.select title from moviewhere director = 'Steven Spielberg'q.2:Find all years that have a movie that received a rating of 4 or 5, and sort them in increasing order.select yearfrom movie, ratingwhere movie.mid = rating.mid and rati 阅读全文

摘要： The whole point of having an index is to speed up search queries by essentially cutting down the number of records/rows in a table that need to be examined.an index is a data structure (most commonly a B- tree) that stores the values for a specific column in a table. An index is created on a column 阅读全文

摘要： super-key:Any key that has more columns than necessary to uniquely identify each row in the table is called a super-key (think of it as a super-set).candidate key:if the key has the minimum amount of columns necessary to uniquely identify each row then it is called a minimal super-key. A minimal sup 阅读全文