Allenlzcoder的博客

LeetCode 149. Max Points on a LineSolution1： 参考花花酱：https://zxi.mytechroad.com/blog/geometry/leetcode-149-max-points-on-a-line/ count by slope Time complexity:O(n2)O(n2)O(n^2) Space complexity:...

LeetCode 68. Text JustificationSolution1：我的答案 除了写的比较慢，没有其他很大的问题。。class Solution {public: vector<string> fullJustify(vector<string>& words, int maxWidth) { vector<s...

LeetCode 6. ZigZag ConversionSolution1：我的答案 总是因为各种各样的傻逼错误导致不能AC，脚踏实地很重要！ 这个笨方法实在是有点慢。class Solution {public: string convert(string s, int numRows) { string res = ""; if (!s....

LeetCode 59. Spiral Matrix IISolution1：我的答案 思路和第54题差不多，就是有点慢。。。。class Solution {public: vector<vector<int>> generateMatrix(int n) { if (n == 1) return {{1}}; vect...

LeetCode 54. Spiral Matrix循环输出矩阵元素，中等难度题目，查数要认真。 Solution1：我的答案class Solution {public: vector<int> spiralOrder(vector<vector<int>>& matrix) { if (!matrix.size()

LeetCode 118. Pascal’s TriangleSolution1：我的答案 简单题目！！！OK!class Solution {public: vector<int> getRow(int rowIndex) { if (!rowIndex) return {1}; vector<int> res; ...

LeetCode 118. Pascal’s TriangleSolution1：我的答案 简单题，一遍过！class Solution {public: vector<vector<int>> generate(int numRows) { if (!numRows) return {}; vector<vecto...

LeetCode 29. Divide Two IntegersSolution1： 参考网址：[1]https://blog.csdn.net/qq_31617121/article/details/80458587 [2]http://www.cnblogs.com/grandyang/p/4431949.html 相当于复杂度优化到logN. 如 100 3 普通方法是 3...

LeetCode 30. Substring with Concatenation of All WordsSolution1： 转载自：http://www.cnblogs.com/grandyang/p/4521224.html，这道题的思路和LeetCode 567. Permutation in String非常像。滑动窗口的思路要牢记啊！！class Solution {pu...

LeetCode 43. Multiply StringsSolution1：我的答案 作为一个hard题，提交一次就过真是让我hin开心啊！！！ 就是方法有点笨。。class Solution {public: string multiply(string num1, string num2) { if (num1 == "0" || num2 == "0"...

LeetCode 76. Minimum Window Substring参考链接： Solution1：

LeetCode 56. Merge IntervalsSolution1：我的答案这道题思路不能，有个坑爹的地方在于输入的区间向量未必是有序的，所以利用优先队列priority_queue来排序/** * Definition for an interval. * struct Interval { * int start; * int end; * ...

LeetCode 57. Insert IntervalSolution1：我的答案 算法很简单，不知道为何会被标记为hard题目/** * Definition for an interval. * struct Interval { * int start; * int end; * Interval() : start(0), end(0) {}...

LeetCode 9. Palindrome NumberSolution1： 不利用字符串class Solution {public: bool isPalindrome(int x) { if (x < 0) return false; int res = 0, base = 1, x_copy = x; while ...

LeetCode 7. Reverse IntegerSolution1：最笨的方法class Solution {public: int reverse(int x) { if (!x) return x; int flag = x > 0? 1: -1; long long res = 0; int tem...

LeetCode 133. Clone GraphSolution1： DFS/记忆化递归，参考网址：http://www.cnblogs.com/grandyang/p/4267628.html 真是一道记忆化递归的好题啊~/** * Definition for undirected graph. * struct UndirectedGraphNode { * in...

LeetCode 140. Word Break IISolution1：我的答案 纯DFS，在第31个case时超时，还是记录一下。。class Solution { // DFSpublic: vector<string> wordBreak(string s, vector<string>& wordDict) { unor...

LeetCode 139. Word BreakSolution1： 记忆化递归的典型套路题 参考网址：https://zxi.mytechroad.com/blog/leetcode/leetcode-139-word-break/ class Solution { //记忆化递归！public: bool wordBreak(string s, vector<st...

LeetCode 115. Distinct SubsequencesSolution1： 不会做。。 参考网址：https://www.youtube.com/watch?v=mPqqXh8XvWY Time complexity: O(|s|∗|t|)O(|s|∗|t|)O(|s| * |t|) Space complexity: O(|s|∗|t|)O(|s|∗|t|)O(|...

LeetCode 639. Decode Ways II参考网址：https://zxi.mytechroad.com/blog/dynamic-programming/leetcode-639-decode-ways-ii/ Solution1： 动态规划 先写清楚思路，再写代码~// Author: Huahua// Runtime: 58 msclass Solut...

LeetCode 300. Longest Increasing SubsequenceSolution1：我的答案 暴力搜索，时间复杂度O(n2)O(n2)O(n^2)class Solution {public: int lengthOfLIS(vector<int>& nums) { int n = nums.size(), res =...

LeetCode 91. Decode WaysSolution1：我的答案 还是记录一下，最容易想到的是DFS，但是在第223/238个case上就超时了。。。class Solution {public: int numDecodings(string s) { //先来一波DFS int res = 0, start = 0; my_num...

LeetCode 72. Edit Distance参考链接：https://zxi.mytechroad.com/blog/dynamic-programming/leetcode-72-edit-distance/ 思路： Solution1： 递归// Author: Huahua// Runtime: 13 msclass Solution {public: ...

LeetCode 64. Minimum Path SumSolution1：标准的动态规划题目class Solution {public: int minPathSum(vector<vector<int>>& grid) { if (!grid.size() || !grid[0].size()) re...

LeetCode 87. Scramble String参考链接：[1]https://blog.csdn.net/makuiyu/article/details/44926439 [2]http://www.cnblogs.com/grandyang/p/4318500.html Solution1： 递归class Solution {public: bool isSc...

LeetCode 97. Interleaving String参考网址：[1]https://www.youtube.com/watch?v=HmAF9xeS_2I [2]http://www.cnblogs.com/grandyang/p/4298664.html 【初始化】这道题的大前提是字符串s1和s2的长度和必须等于s3的长度，如果不等于，肯定返回false。当s1和s2是空...

LeetCode 85. Maximal RectangleSolution1: 一语惊醒梦中人啊，参考链接：https://www.youtube.com/watch?v=2Yk3Avrzauk 根据第84题完成！class Solution {public: int maximalRectangle(vector<vector<char>>&amp

LeetCode 53. Maximum SubarraySolution1：我的答案 动态规划class Solution {public: int maxSubArray(vector<int>& nums) { int n = nums.size(); if (!nums.size()) return -1; ...

LeetCode 120. TriangleSolution1：我的答案 真费劲啊！！！ 啊！！！！！！class Solution {public: int minimumTotal(vector<vector<int>>& triangle) { if (!triangle.size() || !t...

LeetCode 11. Container With Most WaterSolution1： 参考网址：http://www.cnblogs.com/grandyang/p/4455109.html 定义两个指针向中间走，贪心啊。。class Solution {//public: int maxArea(vector<int>& height) {...

LeetCode 3. Longest Substring Without Repeating CharactersSolution1：我的答案 该方法中哈希表记录的是字符出现的次数。标准的贪心算法，超过80%的答案； 如果哈希表记录字符出现的位置则还能进一步优化。class Solution {public: int lengthOfLongestSubstring(str...

LeetCode 714. Best Time to Buy and Sell Stock with Transaction FeeSolution1： 参考网址：http://www.cnblogs.com/grandyang/p/7776979.html sold[i]sold[i]sold[i]表示第iii天卖掉股票此时的最大利润，hold[i]hold[i]hold[i]表示第ii...

LeetCode 309. Best Time to Buy and Sell Stock with CooldownSolution1: 比较有难度的一道动态规划题了！ 参考网址：http://zxi.mytechroad.com/blog/dynamic-programming/leetcode-309-best-time-to-buy-and-sell-stock-with-cool...

LeetCode 188. Best Time to Buy and Sell Stock IVSolution1：我的答案

LeetCode 123. Best Time to Buy and Sell Stock IIISolution1:

LeetCode 122. Best Time to Buy and Sell Stock IISolution1:我的答案 贪心和DP傻傻分不清！class Solution {public: int maxProfit(vector<int>& prices) { int max_pro = 0, n = prices.size(); ...

LeetCode 121. Best Time to Buy and Sell StockSolution1:我的答案 动态规划和贪心不要区分的那么明显嘛~~~class Solution {public: int maxProfit(vector<int>& prices) { int n = prices.size(); ...

LeetCode 45. Jump Game II参考网址：http://www.cnblogs.com/grandyang/p/4373533.html Solution1： 贪心算法，这里贪婪并不是要在能跳的范围中选跳力最远的那个位置，因为这样选下来不一定是最优解，这么一说感觉又有点不像贪婪算法了。我们这里贪的是一个能到达的最远范围，我们遍历当前跳跃能到的所有位置，然后根据该位置上的跳...

LeetCode 55. Jump Game貌似一直就没做几个贪心的题，是时候好好学习一个了。。 参考网址：http://www.cnblogs.com/grandyang/p/4371526.html Solution1：贪心 时间复杂度O(n)O(n)O(n)，空间复杂度O(1)O(1)O(1) 贪婪算法Greedy Algorithm，因为我们并不是很关心每一个位置上的剩余步数，...

LeetCode 69. Sqrt(x)参考网址：http://www.cnblogs.com/grandyang/p/4346413.html Solution1：class Solution {public: int mySqrt(int x) { if (x <= 1) return x; int left = 0, right = ...