/**
* 編寫一個截取字符串的函數，輸入為一個字符串和字節數，輸出為按字節截取的字符串。
* 但是要保證漢字不被截半個，如輸入（“我ABC”，4），應該輸出“我AB”；
* 輸入（“我ABC漢DEF”，6），應該輸出“我ABC”而不是“我ABC”+“漢”的半個
*
* 考點：漢字截半時對應字節的ASCII碼小于0
*/
public static void main(String[] args) throws Exception {
String src = "我ABC漢DEF";
System.out.println(spiltString(src, 4));
System.out.println(spiltString(src, 6));
}
private static String spiltString(String src, int len) throws Exception {
if (src == null || src.equals("")) {
System.out.println("The source String is null!");
return null;
}
byte[] srcBytes = src.getBytes("GBK");
if (len > srcBytes.length) {
len = srcBytes.length;
}
if (srcBytes[len] < 0) {
return new String(srcBytes, 0, --len);
} else {
return new String(srcBytes, 0, len);
}
}
/**
* 在實際開發工作中，對字符串的處理是最常見的編程任務。
* 本題目即是要求程序對用戶輸入的字符串進行處理。具體規則如下：
* a）把每個單詞的首字母變為大寫
* b）把數字與字母之間用下劃線字符（_）分開，使得更清晰
* c）把單詞中間有多個空格的調整為1個空格
* 例如：
* 用戶輸入：
* you and me what cpp2005program
* 則程序輸出：
* You And Me What Cpp_2005_program
*
* 相關文章：http://blog.csdn.net/u013091087/article/details/43793149
*/
public static void main(String[] args) {
System.out.println("please input:");
Scanner scanner = new Scanner(System.in);
String s = scanner.nextLine();
scanner.close();
String[] ss = s.split("\\\\s+"); // \\s表示空格、\\t、\\n等空白字符
for (int i = 0; i < ss.length; i++) {
String up = (ss[i].charAt(0) + "").toUpperCase(); // 大寫
StringBuffer sb = new StringBuffer(ss[i]);
ss[i] = sb.replace(0, 1, up).toString(); // 首字母替換為大寫
Matcher m = Pattern.compile("\\\\d+").matcher(ss[i]);
int fromIndex = 0;
while (m.find()) {
String num = m.group();
int index = ss[i].indexOf(num, fromIndex);
StringBuffer sbNum = new StringBuffer(ss[i]);
ss[i] = sbNum.replace(index, index + num.length(),
"_" + num + "_").toString();
fromIndex = index + num.length() + 2;
if (ss[i].startsWith("_")) { // 去頭"_"
ss[i] = ss[i].substring(1);
}
if (ss[i].endsWith("_")) { // 去尾"_"
ss[i] = ss[i].substring(0, ss[i].length() - 1);
}
}
}
for (int i = 0; i < ss.length - 1; i++) {
System.out.print(ss[i] + " ");
}
System.out.print(ss[ss.length - 1]);
}
/**
* 兩個有序數組的合并函數
* @param a
* @param b
* @return
*/
public static int[] MergeList(int a[], int b[]) {
int result[];
result = new int[a.length + b.length];
//i:用于標示a數組 j：用來標示b數組 k：用來標示傳入的數組
int i = 0, j = 0, k = 0;
while (i < a.length && j < b.length) {
if (a[i] <= b[j]) {
result[k++] = a[i++];
} else {
result[k++] = b[j++];
}
}
/* 后面連個while循環是用來保證兩個數組比較完之后剩下的一個數組里的元素能順利傳入 */
while (i < a.length)
result[k++] = a[i++];
while (j < b.length)
result[k++] = b[j++];
return result;
}
public static int rank(int key, int a[]) {
return rank(key, a, 0, a.length - 1);
}
public static int rank(int key, int a[], int lo, int hi) {
if (lo > hi)
return -1;//error
int mid = lo + (hi - lo) / 2;
if (key < a[mid])
return rank(key, a, lo, mid - 1);
else if (key > a[mid])
return rank(key, a, mid + 1, hi);
else
return mid;
}
/**
* 將數組中奇數放到偶數前面java實現
* 例如：給定 int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9};
* 輸出 int[] nums = {1, 9, 3, 7, 5, 6, 4, 8, 2};
*/
public class TokenCode1 {
public static void main(String[] args) {
// write your code here
int[] nums = {1, 2, 3, 4, 5, 6, 7, 8, 9};
int[] result = convertNums(nums);
System.out.println(Arrays.toString(result));
}
private static int[] convertNums(int[] nums) {
int i = 0;
int j = nums.length - 1;
while (i < j) {
while (i < j && nums[i] % 2 != 0) {
i++;
}
while (i < j && nums[j] % 2 == 0) {
j--;
}
swap(nums, i, j);
}
return nums;
}
private static void swap(int[] nums, int a, int b) {
int temp = nums[a];
nums[a] = nums[b];
nums[b] = temp;
}
}
/**
* 鏈表反轉
*/
public class TokenCode2 {
public static void main(String[] args) {
Node headNode = buildTestNode();
printNodes(headNode);
printNodes(convertNodes(headNode));
}
/**
* 鏈表反轉
* @param node
* @return
*/
private static Node convertNodes(Node node) {
Node pre = null;
Node now = node;
while (now != null) {
Node next = now.child;
now.child = pre;
pre = now;
now = next;
}
return pre;
}
/**
* 生成測試頭節點
* @return
*/
private static Node buildTestNode() {
Node node5 = new Node("5", null);
Node node4 = new Node("4", node5);
Node node3 = new Node("3", node4);
Node node2 = new Node("2", node3);
Node head = new Node("1", node2);
return head;
}
/**
* 打印列表
* @param node
*/
private static void printNodes(Node node) {
System.out.print(node.value);
if (node.child != null) {
System.out.print(" -> ");
printNodes(node.child);
} else {
System.out.println();
}
}
}
/**
* 合并兩個有序鏈表
* 例如
* headA = 1 -> 3 -> 5 -> 7 -> 9
* headB = 2 -> 4 -> 6 -> 8 -> 10
* result = 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8 -> 9 -> 10
*/
public class TokenCode3 {
public static void main(String[] args) {
Node headA = buildTestNode_A();
printNodes(headA);
Node headB = buildTestNode_B();
printNodes(headB);
printNodes(mergeNodes(headA, headB));
}
/**
* 合并數組
* @param headA
* @param headB
* @return
*/
private static Node mergeNodes(Node headA, Node headB) {
if (headA == null) {
return headB;
}
if (headB == null) {
return headA;
}
Node result;
if (headA.value <= headB.value) {
result = headA;
result.next = mergeNodes(headA.next, headB);
} else {
result = headB;
result.next = mergeNodes(headA, headB.next);
}
return result;
}
/**
* 生成測試頭節點
*
* @return
*/
private static Node buildTestNode_A() {
Node node5 = new Node(9, null);
Node node4 = new Node(7, node5);
Node node3 = new Node(5, node4);
Node node2 = new Node(3, node3);
Node head = new Node(1, node2);
return head;
}
/**
* 生成測試頭節點
*
* @return
*/
private static Node buildTestNode_B() {
Node node5 = new Node(10, null);
Node node4 = new Node(8, node5);
Node node3 = new Node(6, node4);
Node node2 = new Node(4, node3);
Node head = new Node(2, node2);
return head;
}
/**
* 打印列表
*
* @param node
*/
private static void printNodes(Node node) {
System.out.print(node.value);
if (node.next != null) {
System.out.print(" -> ");
printNodes(node.next);
} else {
System.out.println();
}
}
}
/**
* 樹的最大深度
*/
public class TokenCode4 {
public static void main(String[] args) {
TreeNode head = buildTestTree();
printTree(head);
System.out.println();
System.out.print("count = " + getCount(head));
}
/**
* 樹的最大深度
* @param treeNode
* @return
*/
private static int getCount(TreeNode treeNode) {
if (treeNode == null) {
return 0;
} else {
int left = getCount(treeNode.left);
int right = getCount(treeNode.right);
if (left > right) {
return left + 1;
} else {
return right + 1;
}
}
}
/**
* 測試樹 1 , 2 , 4 , 5 , 3 , 6 , 7
* @return
*/
private static TreeNode buildTestTree() {
TreeNode node7 = new TreeNode(7, null, null);
TreeNode node6 = new TreeNode(6, null, null);
TreeNode node5 = new TreeNode(5, null, null);
TreeNode node4 = new TreeNode(4, null, null);
TreeNode node3 = new TreeNode(3, node6, node7);
TreeNode node2 = new TreeNode(2, node4, node5);
TreeNode node1 = new TreeNode(1, node2, node3);
return node1;
}
/**
* 遍歷樹
* @param treeNode
*/
private static void printTree(TreeNode treeNode) {
System.out.print(treeNode.value);
if (treeNode.left != null) {
System.out.print(" , ");
printTree(treeNode.left);
}
if (treeNode.right != null) {
System.out.print(" , ");
printTree(treeNode.right);
}
}
}
/**
* 二分法查找
* 給定數組 nums = {3, 6, 7, 9, 15, 20, 26, 33, 56, 63}
* 查找目標數組 33 的下標
*/
public class TokenCode5 {
public static void main(String[] args) {
int[] nums = {3, 6, 7, 9, 15, 20, 26, 33, 56, 63};
int target = 33;
System.out.print("index = " + binarysearch(nums, target));
}
/**
* 二分法查找
*
* @param nums
* @param target
* @return
*/
private static int binarysearch(int[] nums, int target) {
int low = 0;
int high = nums.length - 1;
int mid = 0;
while (low <= high) {
mid = (low + high) / 2;
if (nums[mid] == target) {
return mid;
}
if (nums[mid] > target) {
high = mid - 1;
} else {
low = mid + 1;
}
}
return -1;
}
}
