随笔分类 - Algorithm
摘要：Problem Link: https://atcoder.jp/contests/abc404/tasks/abc404_e Greedy For position i, if there exists a postion j in [i - C[i], i - 1], where A[j] >
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摘要：Problem Link If we pick A[i] the 2nd time, it means we have a cycle. Proof: 1st time we pick A[i], the sum before adding A[i] is x; 2nd time we pick A
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摘要：Problem Link Based on initial observation, it seems that greedily pick the smallest row / column length works. But the last example test case outputs
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摘要：1. The 1st palindromic number is 0, so we do N-- to exclude 0. 2. F(k): the number of palindromic numbers of length k. F(1) = 9; F(2) = 9; F(k) = F(k
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摘要：You are given an array nums which is a permutation of [0, 1, 2, ..., n - 1]. The score of any permutation of [0, 1, 2, ..., n - 1] named perm is defin
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摘要：Incorrect solution: greedily find out how many consecutive S we can convert to all o. Then for the remaining replace operations, try each starting pos
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摘要：Problem Statment Assume the first N - 1 rounds have been played and we are left with a %7 value R. There are 2 cases depending on who plays the last r
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摘要：Problem Statement If we add edges between every pair of sets that have shared elements, there will be O(N^2) edges to traverse. Instead, we can add N
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摘要：The key observation is that there is always at most 1 cell that violates both conditions. Proof: if x violates both conditions, that means all other n
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摘要：You are given an undirected graph (the "original graph") with n nodes labeled from 0 to n - 1. You decide to subdivide each edge in the graph into a c
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摘要：Problem Statement dp[i][j]: the number of subsets of A[0, i] whose sum is j. dp[0][0] = 1, there is only 1 way of not picking anything from an empty a
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摘要：You are given a 2D integer array, queries. For each queries[i], where queries[i] = [ni, ki], find the number of different ways you can place positive
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摘要：Problem Statement 1. N is up to 35, so trying all possible subsequences is too slow (2^35). We can apply the meet in the middle technique and divide A
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摘要：You are given a 2D integer array intervals, where intervals[i] = [lefti, righti] describes the ith interval starting at lefti and ending at righti (in
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摘要：There are n uniquely-sized sticks whose lengths are integers from 1 to n. You want to arrange the sticks such that exactly k sticks are visible from t
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摘要：Problem Link Dp[i][j]: the number of possible ways from s[0, i] with the ith statement ending with indentation j. dp[0][0] = 1, the 1st statement must
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摘要：A. Counting Kangaroos is Fun There can be only at most N / 2 hold and held pairs based the problem's statment. So a greedy approach is just to divide
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摘要：Problem First I thought about modelling this problem as a directed graph, where between each pair of nodes, an edge represents a valid < > or > < tran
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摘要：Problem S: the set of numbers said by player 1; P: the set of numbers said by player 2; S^2 * P = a; S * P^2 = b; a * b = (S * P)^3, so a * b must be
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摘要：Problem Each fence is increased at most 2 times, so dp[i][j] is the min cost to make A[0, i] great with the last fence A[i] increased j times. The ans
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