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Given an array of words and a lengthL, format the text such that each line has exactlyLcharacters and is fully (left and right) justified.You should pack your words in a greedy approach; that is, pack as many words as you can in each line. Pad extra spaces' 'when necessary so that each line 阅读全文
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Reverse a linked list from positionmton. Do it in-place and in one-pass.For example:Given1->2->3->4->5->NULL,m= 2 andn= 4,return1->4->3->2->5->NULL.Note:Givenm,nsatisfy the following condition:1 ≤m≤n≤ length of list.画图会比较容易理解 1 /** 2 * Definition for singly-linked list. 阅读全文
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You are given annxn2D matrix representing an image.Rotate the image by 90 degrees (clockwise).Follow up:Could you do this in-place?需要O(N)的辅助空间，应该有个O(1)空间的。但似乎比较复杂。 1 class Solution { 2 public: 3 void rotate(vector<vector<int> > &matrix) { 4 // Start typing your C/C++ solution below 5 阅读全文
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The string"PAYPALISHIRING"is written in a zigzag pattern on a given number of rows like this: (you may want to display this pattern in a fixed font for better legibility)P A H NA P L S I I GY I RAnd then read line by line:"PAHNAPLSIIGYIR"Write the code that will take a string and 阅读全文
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Given a linked list, reverse the nodes of a linked listkat a time and return its modified list.If the number of nodes is not a multiple ofkthen left-out nodes in the end should remain as it is.You may not alter the values in the nodes, only nodes itself may be changed.Only constant memory is allowed 阅读全文
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Given a list, rotate the list to the right bykplaces, wherekis non-negative.For example:Given1->2->3->4->5->NULLandk=2,return4->5->1->2->3->NULL.注意一些边界的处理，找到n-k+1个节点后处理移位。 1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next 阅读全文
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Validate if a given string is numeric.Some examples:"0"=>true" 0.1 "=>true"abc"=>false"1 a"=>false"2e10"=>trueNote:It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementin 阅读全文
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Given a string containing just the characters'(',')','{','}','['and']', determine if the input string is valid.The brackets must close in the correct order,"()"and"()[]{}"are all valid but"(]"and"([)]"are not.利用一 阅读全文
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Implementint sqrt(int x).Compute and return the square root ofx.牛顿迭代 1 class Solution { 2 public: 3 int sqrt(int x) { 4 // Start typing your C/C++ solution below 5 // DO NOT write int main() function 6 double ans = x; 7 8 while(abs(ans * ans - x) > 0.0001... 阅读全文
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Given an integern, generate a square matrix filled with elements from 1 ton2in spiral order.For example,Givenn=3,You should return the following matrix:[ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ]]继续DFS 1 class Solution { 2 private: 3 int step[4][2]; 4 bool canUse[100][100]; 5 public: 6 void ... 阅读全文
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Given a matrix ofmxnelements (mrows,ncolumns), return all elements of the matrix in spiral order.For example,Given the following matrix:[ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8, 9 ]]You should return[1,2,3,6,9,8,7,4,5].开一个数组用来保存，之前这个单元是否被使用过，并配合边界判断，DFS，最后得出结果。空间复杂度O(n*m)，时间O(n*m) 1 class Solution { 2 pri 阅读全文
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Given amxnmatrix, if an element is 0, set its entire row and column to 0. Do it in place.Follow up:Did you use extra space?A straight forward solution using O(mn) space is probably a bad idea.A simple improvement uses O(m+n) space, but still not the best solution.Could you devise a constant space so 阅读全文
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Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates in the array.Here are few examples.[1,3,5,6], 5 → 2[1,3,5,6], 2 → 1[1,3,5,6], 7 → 4[1,3,5,6], 0 → 0二分搜索的修改版 1 class S 阅读全文
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Mergeksorted linked lists and return it as one sorted list. Analyze and describe its complexity.类似于Merge Sort的方法做k-1次 1 /** 2 * Definition for singly-linked list. 3 * struct ListNode { 4 * int val; 5 * ListNode *next; 6 * ListNode(int x) : val(x), next(NULL) {} 7 * }; 8 */ 9 class... 阅读全文