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加油冲

This commit is contained in:
Zerroi 2024-03-25 20:14:01 +08:00
parent 2e3d5486bc
commit cca9883795
13 changed files with 538 additions and 6 deletions
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23
com/zerroi/leetcode/Three21/IsValidBracket.java Normal file
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package com.zerroi.leetcode.Three21;
import java.util.Stack;
public class IsValidBracket {
public static void main(String[] args) {
}
}
class SolutionFirst {
public boolean isValid(String s) {
Stack<Character> stack = new Stack<>();
for (char c : s.toCharArray()) {
if (c == '(') stack.push(')');
else if (c == '[') stack.push(']');
else if (c == '{') stack.push('}');
else if (stack.isEmpty() || stack.pop() != c) return false;
}
return stack.isEmpty();
}
}

10
com/zerroi/leetcode/Three21/MinStackClass.java Normal file
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package com.zerroi.leetcode.Three21;
import java.util.*;
import java.util.stream.Collectors;
import java.util.stream.Stream;
public class MinStackClass {
}

41
com/zerroi/leetcode/Three21/SimplifyPath.java Normal file
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package com.zerroi.leetcode.Three21;
import java.util.Queue;
import java.util.Stack;
public class SimplifyPath {
public static void main(String[] args) {
SolutionSecond solutionSecond = new SolutionSecond();
// String s = solutionSecond.simplifyPath("/a//b////c/d//././/..");
String s = solutionSecond.simplifyPath("/../");
System.out.println("s = " + s);
}
}
class SolutionSecond {
public String simplifyPath(String path) {
String[] strs = path.split("/");
Stack<String> stack = new Stack<>();
for (String str : strs) {
if ("..".equals(str)) {
if (!stack.isEmpty()) stack.pop();
} else if (!str.isEmpty() && !str.equals(".")) {
stack.push(str);
}
}
StringBuffer res = new StringBuffer();
if (stack.isEmpty()) {
res.append("/");
} else {
while (!stack.isEmpty()) {
res.append("/");
res.append(stack.removeFirst());
}
}
return res.toString();
}
}

98
com/zerroi/leetcode/Three22/BasicCalculator.java Normal file
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package com.zerroi.leetcode.Three22;
import java.util.*;
public class BasicCalculator {
public static void main(String[] args) {
Solution solution = new Solution();
int res = solution.calculate("(1+(4+5+2)-3)+(6+8)");
System.out.println("res = " + res);
}
}
class Solution {
private Map<Character, Integer> map = new HashMap<>();
private Deque<Character> opQue = new LinkedList<>();
private Deque<Integer> numQue = new LinkedList<>();
private void compute() {
int b = numQue.pollLast();
int a = numQue.pollLast();
int op = opQue.pollLast();
int ans = 0;
switch (op) {
case '+':
ans = a + b;
break;
case '-':
ans = a - b;
break;
case '*':
ans = a * b;
break;
case '/':
ans = a / b;
break;
default:
break;
}
numQue.addLast(ans);
}
public int calculate(String s) {
s = s.replaceAll(" ", "");
map.put('+', 0);
map.put('-', 0);
map.put('*', 1);
map.put('/', 1);
map.put('(', -1);
map.put(')', -1);
numQue.addLast(0);
char[] sArr = s.toCharArray();
int n = sArr.length;
for (int i = 0; i < n; i++) {
// 截取数字
if (sArr[i] >= '0' && sArr[i] <= '9') {
int start = i;
while (i < n && sArr[i] >= '0' && sArr[i] <= '9') {
++i;
}
int num = Integer.parseInt(s.substring(start, i));
numQue.addLast(num);
}
if (i >= n) {
break;
}
// 如果是左括号直接入栈
if (sArr[i] == '(') {
opQue.addLast(sArr[i]);
// 右括号一直计算知道找到左括号
} else if (sArr[i] == ')') {
while (opQue.peekLast() != '(') {
compute();
}
opQue.pollLast();
// 操作符
} else {
// 判断是否出现了(- 或者 (+这种情况,那么进行操作数栈补0
if (i > 0 && sArr[i - 1] == '(') {
numQue.addLast(0);
}
// 如果当前操作符的优先级小于栈顶优先级
if (!opQue.isEmpty() && map.get(opQue.peekLast()) >= map.get(sArr[i])) {
compute();
}
opQue.addLast(sArr[i]);
}
}
// 如果最后还有元素要继续计算
while (!opQue.isEmpty()) {
compute();
}
return numQue.peekLast();
}
}

49
com/zerroi/leetcode/Three22/EvalRPN.java Normal file
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package com.zerroi.leetcode.Three22;
import java.util.Deque;
import java.util.LinkedList;
import java.util.Stack;
public class EvalRPN {
public static void main(String[] args) {
SolutionFirst solutionFirst = new SolutionFirst();
// int res = solutionFirst.evalRPN(new String[]{"2", "1", "+", "3", "*"});
int res = solutionFirst.evalRPN(new String[]{"10","6","9","3","+","-11","*","/","*","17","+","5","+"});
System.out.println("res = " + res);
}
}
class SolutionFirst {
public int evalRPN(String[] tokens) {
Stack<Integer> stack = new Stack<>();
int n1 = 0, n2 = 0;
for (String token : tokens) {
switch (token) {
case "+":
n1 = stack.pop();
n2 = stack.pop();
stack.add(n1 + n2);
break;
case "-":
n1 = stack.pop();
n2 = stack.pop();
stack.add(n2 - n1);
break;
case "*":
n1 = stack.pop();
n2 = stack.pop();
stack.add(n1*n2);
break;
case "/":
n1 = stack.pop();
n2 = stack.pop();
stack.add(n2 / n1);
break;
default:
stack.add(Integer.valueOf(token));
break;
}
}
return stack.isEmpty() ? 0 : stack.getFirst();
}
}

37
com/zerroi/leetcode/Three22/HasCycle.java Normal file
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package com.zerroi.leetcode.Three22;
public class HasCycle {
public static void main(String[] args) {
ListNode l1 = new ListNode(1);
ListNode l2 = new ListNode(1);
l1.next = l2;
SolutionThird solutionThird = new SolutionThird();
boolean res = solutionThird.hasCycle(l1);
System.out.println("res = " + res);
}
}
class SolutionThird {
public boolean hasCycle(ListNode head) {
if (head.next == null) return false;
ListNode slow = head;
ListNode fast = head;
while (fast.next != null) {
slow = slow.next;
fast = fast.next.next;
if (slow == fast) {
return true;
}
}
return false;
}
}
class ListNode {
int val;
ListNode next;
ListNode(int x) {
val = x;
next = null;
}
}

57
com/zerroi/leetcode/Three23/AddTwoNumbers.java Normal file
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package com.zerroi.leetcode.Three23;
public class AddTwoNumbers {
public static void main(String[] args) {
ListNode l1 = new ListNode(2, new ListNode(2, new ListNode(3)));
ListNode l2 = new ListNode(5, new ListNode(6, new ListNode(4)));
SolutionFirst solutionFirst = new SolutionFirst();
ListNode listNode = solutionFirst.addTwoNumbers(l1, l2);
}
}
class ListNode {
int val;
ListNode next;
ListNode() {}
ListNode(int val) { this.val = val; }
ListNode(int val, ListNode next) { this.val = val; this.next = next; }
}
class SolutionFirst {
public ListNode addTwoNumbers(ListNode l1, ListNode l2) {
ListNode head = new ListNode(-1);
ListNode cur = head;
int carry = 0;
int a = 0, b = 0;
int value = 0;
while (l1 != null || l2 != null) {
if (l1 == null) {
a = 0;
} else {
a = l1.val;
}
if (l2 == null) {
b = 0;
} else {
b = l2.val;
}
value = a + b + carry;
carry = value / 10;
value = value % 10;
cur.next = new ListNode(value);
cur = cur.next;
if (l1 != null) {
l1 = l1.next;
}
if (l2 != null) {
l2 = l2.next;
}
if (carry != 0) {
cur.next = new ListNode(1);
}
}
return cur;
}
}

36
com/zerroi/leetcode/Three23/MergeTwoLists.java Normal file
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package com.zerroi.leetcode.Three23;
public class MergeTwoLists {
public static void main(String[] args) {
ListNode l1 = new ListNode(1, new ListNode(2, new ListNode(4)));
ListNode l2 = new ListNode(1, new ListNode(3, new ListNode(4)));
SolutionSecond solutionSecond = new SolutionSecond();
solutionSecond.mergeTwoLists(l1, l2);
}
}
class SolutionSecond {
public ListNode mergeTwoLists(ListNode list1, ListNode list2) {
if (list1 == null || list2 == null) {
return list1 == null ? list2 : list1;
}
ListNode pre = new ListNode(-1);
ListNode cur = pre;
while (list1 != null && list2 != null) {
if (list1.val <= list2.val) {
cur.next = list1;
list1 = list1.next;
} else {
cur.next = list2;
list2 = list2.next;
}
cur = cur.next;
if (list1 == null) {
cur.next = list2;
}
if (list2 == null) {
cur.next = list1;
}
}
return pre.next;
}
}

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com/zerroi/leetcode/Three23/ReverseList.java Normal file
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package com.zerroi.leetcode.Three23;
public class ReverseList {
public static void main(String[] args) {
}
}
class SolutionThird {
public ListNode reverseList(ListNode head) {
ListNode pre = null;
ListNode cur = head;
ListNode temp = null;
while (cur != null) {
temp = cur.next;
cur.next = pre;
pre = cur;
cur = temp;
}
return pre;
}
}

52
com/zerroi/leetcode/Three24/ReverseBetween.java Normal file
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package com.zerroi.leetcode.Three24;
public class ReverseBetween {
public static void main(String[] args) {
}
}
class ListNode {
int val;
ListNode next;
ListNode() {}
ListNode(int val) { this.val = val; }
ListNode(int val, ListNode next) { this.val = val; this.next = next; }
}
class Solution {
public ListNode reverseBetween(ListNode head, int left, int right) {
if (left == right) return head;
ListNode dummy1 = new ListNode(-1);
ListNode dummy2 = new ListNode(-1);
ListNode cur1 = dummy1;
ListNode cur2 = dummy2;
for (int i = 0; i < left - 1; i++) {
cur1.next = new ListNode(head.val);
cur1 = cur1.next;
head = head.next;
}
for (int i = left; i <= right; i++) {
cur2.next = new ListNode(head.val);
cur2 = cur2.next;
head = head.next;
}
ListNode reversed = reverse(dummy2.next);
cur1.next = reversed;
cur2.next = head;
return dummy1.next;
}
private ListNode reverse(ListNode head) {
ListNode pre = null;
ListNode cur = head;
ListNode temp;
while (cur != null) {
temp = cur.next;
cur.next = pre;
pre = cur;
cur = temp;
}
return pre;
}
}

56
com/zerroi/leetcode/Three25/DeleteDuplicates.java Normal file
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package com.zerroi.leetcode.Three25;
public class DeleteDuplicates {
public static void main(String[] args) {
// ListNode head = constructLinkedList(new int[]{1, 2, 3, 3, 4, 4, 5});
ListNode head = constructLinkedList(new int[]{1, 1});
SolutionSecond solutionSecond = new SolutionSecond();
ListNode res = solutionSecond.deleteDuplicates(head);
while (res != null) {
System.out.println("res.val = " + res.val);
res = res.next;
}
}
public static ListNode constructLinkedList(int[] nums) {
if (nums == null || nums.length == 0) {
return null;
}
ListNode dummy = new ListNode(); // 创建一个虚拟头节点
ListNode current = dummy;
for (int num : nums) {
current.next = new ListNode(num);
current = current.next;
}
return dummy.next; // 返回真正的头节点
}
}
class SolutionSecond {
public ListNode deleteDuplicates(ListNode head) {
if (head == null || head.next == null) return head;
ListNode dummy = new ListNode(-1);
dummy.next = head;
// pre指针为cur的前驱节点
ListNode pre = dummy;
// cur为当前节点
ListNode cur = head;
while (cur != null && cur.next != null) {
// 如果出现当前节点的值等于其下一节点值，要一直循环找到不相等的
if (cur.val == cur.next.val) {
int duplicate = cur.val;
while (cur != null && cur.val == duplicate) {
cur = cur.next;
}
pre.next = cur;
} else {
pre = pre.next;
cur = cur.next;
}
}
return dummy.next;
}
}

55
com/zerroi/leetcode/Three25/RemoveNthFromEnd.java Normal file
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package com.zerroi.leetcode.Three25;
public class RemoveNthFromEnd {
public static void main(String[] args) {
// ListNode head = new ListNode(1, new ListNode(2, new ListNode(3, new ListNode(4, new ListNode(5)))));
ListNode head = new ListNode(1, new ListNode(2));
SolutionFirst solutionFirst = new SolutionFirst();
solutionFirst.removeNthFromEnd(head, 2);
}
}
class ListNode {
int val;
ListNode next;
ListNode() {
}
ListNode(int val) {
this.val = val;
}
ListNode(int val, ListNode next) {
this.val = val;
this.next = next;
}
}
class SolutionFirst {
public ListNode removeNthFromEnd(ListNode head, int n) {
if(head == null) return null;
ListNode cur = head;
int length = length(head);
if(length == 1) return null;
if (length == n) return head.next;
ListNode dummy = new ListNode(0, head);
for (int i = 1; i <= length - n; i++) {
cur = cur.next;
dummy = dummy.next;
}
dummy.next = cur.next;
return head;
}
private int length(ListNode head) {
int length = 0;
while (head != null) {
length++;
head = head.next;
}
return length;
}
}

8
com/zerroi/leetcode/ThreeFive/Rotate.java
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@ -15,17 +15,13 @@ class SolutionSecond {
public void rotate(int[] nums, int k) {
k = k % nums.length;
int[] temp = new int[k];
for (int i = 0; i < k; i++) {
temp[i] = nums[nums.length - k + i];
}
System.arraycopy(nums, nums.length - k, temp, 0, k);
for (int i = nums.length - k; i >= 0; i--) {
nums[i + k] = nums[i];
}
for (int i = 0; i < k; i++) {
nums[i] = temp[i];
}
System.arraycopy(temp, 0, nums, 0, k);
}
public void rotateReverse(int[] nums, int k) {