令$nex_{i}=\min_{i<j,p_{i}<p_{j}}j$(即$i$的第2类边),若不存在此类$j$则$nex_{i}=n+1$ 建一棵树,其以0为根,且$1\le i\le n$的父亲为$\max_{j<i,p_{i}<p_{j}}j$(不存在则为0),以下记作$fa_{i}$ 每一次选择$(i,nex_{i})$,都可以看作有一个收益$\Delta_{i}=b_{i}-\sum_{j=i}^{nex_{i}-1}a_{j}$ 问题也可以看作选择若干个节点$p_{1}&…

Given a set of words (without duplicates), find all word squares you can build from them. A sequence of words forms a valid word square if the kth row and column read the exact same string, where 0 ≤ k < max(numRows, numColumns). For example, the wor…

本文介绍一种利用移动最小二乘法来实现图像变形的方法,该方法由用户指定图像中的控制点,并通过拖拽控制点来驱动图像变形.假设p为原图像中控制点的位置,q为拖拽后控制点的位置,我们利用移动最小二乘法来为原图像上的每个像素点v构建相应的仿射变换lv(x),并通过该变换来计算得到图像变形后的位置: 其中权重wi的表达式为wi = 1/|pi - v|2α. 仿射变换lv(x)由两部分组成lv(x) = xM + T,其中M为线性转换矩阵,T为平移量.事实上将最小化表达式对变量T求偏导后可以得到T的表达式T…

Given a set of words (without duplicates), find all word squares you can build from them. A sequence of words forms a valid word square if the kth row and column read the exact same string, where 0 ≤ k < max(numRows, numColumns). For example, the wor…

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n. ExampleGiven n = 12, return 3 because 12 = 4 + 4 + 4Given n = 13, return 2 because 13 = 4 + 9 LeetCode上的原题,请参见我之前的博客Perfect Sq…

Counting Squares Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 1885    Accepted Submission(s): 946 Problem Description Your input is a series of rectangles, one per line. Each rectangle is sp…

[转载请注明出处]http://www.cnblogs.com/mashiqi 在回归问题中,偶尔我们会遇到求方差的估计的情况.举了例子,我们常常通过Gaussian分布${\cal N}(\mu ,{\sigma^2})$的样本集合$\{x_i\}_{i=1}^n$去估计分布的参数$\mu,\sigma^2$.对$\mu$的估计应该大家都很熟悉了:$\hat{\mu}=\bar{x} =\frac{1}{n} \sum_{i=1}^n x_i$,然而,对$\sigma^2$的估计,在教科书中,…

题目链接: I. Special Squares There are some points and lines parellel to x-axis or y-axis on the plane. If arbitrary chosen two lines parallel to x-axis and two lines parallel to y-axis, one rectangle, or sometimes a square, will be formed. If a square i…

7.5 Given two squares on a two-dimensional plane, find a line that would cut these two squares in half. Assume that the top and the bottom sides of the square run parallel to the x-axis 这道题给了我们两个正方形,让我们求一条可以讲这两个正方形平均分为两个部分的直线,前提是两个正方形都和x轴平行.那么我们首先要知道…

二分.... Squares Time Limit: 3500MS Memory Limit: 65536K Total Submissions: 14530 Accepted: 5488 Description A square is a 4-sided polygon whose sides have equal length and adjacent sides form 90-degree angles. It is also a polygon such that rotating a…