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此贴为汇总贴 673. Number of Longest Increasing Subsequence 075. Sort Colors 009. Palindrome Number 008. String to Integer (atoi) 007. Reverse Integer 006. Z 阅读全文
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思路：设dp[i][j] 为i到j内回文子串的个数。先枚举所有字符串区间。再依据容斥原理。 那么状态转移方程为 dp[i][j] = dp[i][j-1] + dp[i+1][j] - dp[i+1][j-1] 如果 a[i] = a[j] , dp[i][j] += (dp[i+1][j-1] + 阅读全文
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算法 1 设半径为$R$。 $x = r \ast cos(\theta)$ $y = r \ast sin(\theta)$ 其中 $0\leqslant r \leqslant R$，$t$为0-1均匀分布产生的随机数，$r = sqrt(t) \ast R$，$\theta = 2\pi \a 阅读全文
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Given a (singly) linked list with head node root, write a function to split the linked list into k consecutive linked list "parts". The length of each 阅读全文
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You are given two non-empty linked lists representing two non-negative integers. The most significant digit comes first and each of their nodes contai 阅读全文
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You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need t 阅读全文
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Given a complete binary tree, count the number of nodes. Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, ex 阅读全文
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Given a binary tree, find the maximum path sum. For this problem, a path is defined as any sequence of nodes from some starting node to any node in th 阅读全文
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Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 whic 阅读全文
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Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum. For example:Given the below binary tree and sum 阅读全文
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Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. F 阅读全文