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Valid Palindrome
- 博客分类:
- Leetcode
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.
For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome.
Note:Have you consider that the string might be empty? This is a good que ...
转载:Jackson 框架,轻易转换JSON
- 博客分类:
- 转载
JSON本身就是个简单的不能再简单的玩意,既然要和java做转换,必然有些开源的玩意,貌似Codehaus的Jackson还是比较不错,转载一篇全面介绍以作纪念。
Jackson 框架,轻易转换JSON
Jackson可以轻松的将Java对象转换成json对象和xml ...
求非递减数组中最小的绝对值
- 博客分类:
- 每日一题
给定一个有序整数序列(非递减序),可能包含负数,找出其中绝对值最小的元素,比如给定序列-5, -3, -1, 2, 8 则返回1。
public class MinAbs {
public static int calculate(int[] array) {
return calculate(array, 0, array.length - 1);
}
public static int calculate(int[] array, int low, int high) {
if (low == high) {
...
给定含有n个元素的整型数组a,其中包括0元素和非0元素,对数组进行排序,要求: 1. 排序后所有0元素在前,所有非零元素在后,且非零元素排序前后相对位置不变 2. 不能使用额外存储空间 例子如下 输入 0, 3, 0, 2, 1, 0, 0 输出 0, 0, 0, 0, 3, 2, 1
弱逼解法:
public class MoveZero {
public static void doMove(int[] array) {
for (int i = array.length - 2; i >= 0; i--) {
if (ar ...
ubuntu 安装 PostgreSQL
- 博客分类:
- 数据库
参考官方文档安装PostgreSQL9.1
apt-get install postgresql-9.1
这包括以下主要packages
postgresql-client-9.1 - client libraries and client binaries
postgresql-9.1 - core database server
postgresql-contrib-9.1 - additional supplied modules
libpq-dev - libraries and headers for C language frontend developmen ...
今天在尝试使用jetty7+cometd+spring的archetype建立工程时,无法按照reference预期的出现正常的访问结果,出现了org.apache.jasper.JasperException: java.err.nojdk。
org.apache.jasper.JasperException: java.err.nojdk
at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:89)
at org.apache.jasper.compi ...
最大连续子数组的积
不考虑溢出,注意多个0,多个负数,还有结果是1的情况
public class MaxSubMultiplication {
public static int calculate(int[] array) {
int lastZeroIndex = -1;
int indexOfFirstNegative = -1;
int indexOfLastNegative = -1;
int mulBeforeFirst = 1;
int mulAfterLast = 1;
...
最大公约数
public class Euclid {
public static int gcd(int m, int n) {
int tmp = 0;
do {
tmp = n % m;
n = m;
m = tmp;
} while (tmp != 0);
return n;
}
public static void main(String[] args) {
System.out.p ...
最大子数组之和
给定一个整型数组a,求出最大连续子段之和,如果和为负数,则按0计算,比如1, 2, -5, 6, 8则输出14
public class MaxSubSum {
public static int calculate(int[] array) {
int max = 0;
int tmp = 0;
for (int i = 0; i <= array.length-1; i++) {
if (tmp + array[i] > 0) {
...
快排
public class QuickSort {
public static void sort(Comparable[] array) {
sort(array, 0, array.length - 1);
}
public static void sort(Comparable[] array, int low, int high) {
if (low >= high) {
return;
}
int i = low + 1;
...
两数组中满足给定和的数对
- 博客分类:
- 每日一题
求两数组中满足给定和的数对
给定两个有序整型数组a和b,各有n个元素,求两个数组中满足给定和的数对, 即对a中元素i和b中元素j,满足i + j = s(s已知)
public class PairSummation {
public static void execute(int[] a, int[] b, int s) {
assert (a.length == b.length);
int i = 0;
int j = b.length - 1;
int repeat = 0;
...
数组全排列,不考虑重复值
public class AllPermutation {
public static void doPermute(Character[] array) {
doPermute(array, 0);
}
public static void doPermute(Character[] array, int start) {
if (start == array.length - 1) {
Utils.print(array);
return;
...
递归汉诺塔
public class HanoiQuestion {
private static void move(char from, char to) {
System.out.println("move the top plate from " + from + " to " + to);
}
public static void hanoi(char from, char to, char mid, int index) {
if (index == 1)
...
合并两个数组
给定含有n个元素的有序(非降序)整型数组a和含有m个元素的有序(非降序)整型数组b。合并两个数组中的元素到整型数组c,要求去除重复元素并保持c有序(非降序)。例子如下 a = 1, 2, 4, 8 b = 1, 3, 5, 8 c = 1, 2, 3, 4, 5, 8
public class MergeArray {
public static int[] doMerge(int[] a, int[] b) {
int[] tmp = new int[a.length + b.length];
tmp[0] = 0;
int i = ...