Desperate_gh的博客

暴力法：会超时class Solution { public int nthUglyNumber(int n) { int[] mark = new int[n]; int index = 0; for (int i = 1; ; i++) { int temp = i; while (temp != 1 && temp % 5 == 0) { temp.

class Solution { public int getIndex(char target, char[] c_s, int start, int end) { // 包含 start 和 end for (int i = end; i >= start; i--) { if (c_s[i] == target) { return i; } } return..

dp 数组：class Solution { public int maxValue(int[][] grid) { int m = grid.length, n = grid[0].length; int[][] dp= new int[m][n]; dp[0][0] = grid[0][0]; for (int i = 0; i < m; i++) { for (int j = 0; j < .

class Solution { public int maxSubArray(int[] nums) { int pre = nums[0], max = nums[0]; for (int i = 1; i < nums.length; i++) { pre = Math.max(pre + nums[i], nums[i]); max = Math.max(pre, max); } .

public class Solution { public int jumpFloorII(int target) { int[] dp = new int[target + 1]; dp[0] = 1; dp[1] = 1; for (int i = 2; i <= target; i++) { for (int j = 0; j < i; j++) { dp[i.

public class Solution { public int rectCover(int target) { if (target == 0 || target == 1 || target == 2) { return target; } int a = 1, b = 2, c = 0; for (int i = 3; i <= target; i++) { c = a..

class Solution { public int numWays(int n) { if (n == 0 || n == 1) { return 1; } int[] dp = new int[n + 1]; dp[1] = 1; dp[2] = 2; for (int i = 3; i <= n; i++) { dp[i] = (dp[i ..

class Solution { public int fib(int n) { int a = 0, b = 1, sum = 0; for (int i = 0; i < n; i++) { sum = (a + b) % 1000000007; a = b; b = sum; } return a; }}

暴力法：（超时）class Solution { public int reversePairs(int[] nums) { int sum = 0; for (int i = 0; i < nums.length - 1; i++) { for (int j = i + 1; j < nums.length; j++) { if (nums[i] > nums[j]) { .

选择排序：class Solution { public void swap(String[] str, int i, int j) { String temp = str[i]; str[i] = str[j]; str[j] = temp; } public String minNumber(int[] nums) { int len = nums.length; String[] str = n.

class Solution { public void swap(int[] nums, int i, int j) { int temp = nums[i]; nums[i] = nums[j]; nums[j] = temp; } public int[] exchange(int[] nums) { int i = 0, j = nums.length - 1; while (i < j).

容易想的方法：class Solution { public void dfs (char[] c_str, int[] used, int depth, int len, StringBuffer sb, List<String> res) { if (depth == len) { String temp = new String(sb); if (!res.contains(temp)) { .

深度优先DFS:class Solution { private int cnt = 0; public int byteSum (int i, int j) { int sum = 0; while (i != 0) { sum += i %10; i /= 10; } while (j != 0) { sum += j % 10; .

class Solution { public boolean dfs(char[][] board, int i, int j, char[] words, int k) { if (i < 0 || i >= board.length || j < 0 || j >= board[0].length || board[i][j] != words[k]) { return false; } if..

class Solution { public double myPow(double x, int n) { double res = 1.0; long b = n; if (x == 0) { return 0; } if (b < 0) { x = 1 / x; b = -b; } while (b ..

class Solution { public int missingNumber(int[] nums) { int i = 0, j = nums.length - 1; while (i <= j) { int m = (i + j) / 2; if (nums[m] == m) { i = m + 1; } else{ .

二分：class Solution { public int search(int[] nums, int target) { int i = 0, j = nums.length - 1; while (i <= j) { int m = (i + j) / 2; if (nums[m] <= target) { i = m + 1; } else.

class Solution { public int minArray(int[] numbers) { for (int i = 0; i < numbers.length - 1; i++) { if (numbers[i] > numbers[i + 1]) { return numbers[i + 1]; } } return numbers[0];.

class Solution { public int maxProfit(int[] prices) { int maxProfit = 0; for (int i = 0; i < prices.length - 1; i++) { for (int j = i + 1; j < prices.length; j++) { if (prices[j] - prices[i] > maxP..

class Solution { public int cuttingRope(int n) { if (n <= 3) { return n - 1; } int a = n / 3, b = n % 3; if (b == 0) { return (int)Math.pow(3, a); } if (b == 1) { .

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public TreeNode lowestCommonAncestor(TreeNode root, TreeNo..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public TreeNode lowestCommonAncestor(TreeNode root, TreeNo..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public int recur(TreeNode root) { if (root == null..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { private int depth = 0, maxDepth = 0; public void dfs(Tr.

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { private int res, k; public void dfs(TreeNode root) { ..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */public class Codec { // Encodes a tree to a single string. public Strin.

/*// Definition for a Node.class Node { public int val; public Node left; public Node right; public Node() {} public Node(int _val) { val = _val; } public Node(int _val,Node _left,Node _right) { val = _val..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public void backtracking(TreeNode node, int target, ArrayL..

class Solution { public boolean verify(int[] postorder, int start, int end) { if (start >= end) { return true; } int i = start; while (postorder[i] < postorder[end]) { i++; } ..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public List<List<Integer>> levelOrder(TreeNode..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public List<List<Integer>> levelOrder(TreeNode..

// return res.stream().mapToInt(Integer::valueOf).toArray();/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Sol...

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public boolean isSymmetrical(TreeNode left, TreeNode righ..

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public TreeNode mirrorTree(TreeNode root) { if (ro..

public class Solution { private int[] cnts = new int[128]; private Queue<Character> queue = new LinkedList<Character>(); //Insert one char from stringstream public void Insert(char ch) { cnts[ch]++; queue.ad.

删除链表中重复的结点/* public class ListNode { int val; ListNode next = null; ListNode(int val) { this.val = val; }}*/public class Solution { public ListNode deleteDuplication(ListNode pHead) { ListNode vHead = new ListNode

(也是 leetcode 的142)/** * Definition for singly-linked list. * class ListNode { * int val; * ListNode next; * ListNode(int x) { * val = x; * next = null; * } * } */public class Solution { public ListNode detec.

class Solution { public void reverse(char[] str, int start, int end) { while (start < end) { char temp = str[start]; str[start] = str[end]; str[end] = temp; start++; end--; } } public String reverseLeftWords(String s, int .

/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */class Solution { public boolean isHaveSubTree(TreeNode A, TreeNode B) { ..

/*public class TreeLinkNode { int val; TreeLinkNode left = null; TreeLinkNode right = null; TreeLinkNode next = null; TreeLinkNode(int val) { this.val = val; }}*/public class Solution { public TreeLinkNode GetNext(.