原题链接在这里:https://leetcode.com/problems/minimum-number-of-vertices-to-reach-all-nodes/description/
题目:
Given a directed acyclic graph, with n vertices numbered from 0 to n-1, and an array edges where edges[i] = [fromi, toi] represents a directed e…
原题链接在这里:https://leetcode.com/problems/minimum-number-of-flips-to-convert-binary-matrix-to-zero-matrix/description/
题目:
Given a m x n binary matrix mat. In one step, you can choose one cell and flip it and all the four neighbors of it if they exi…
原题链接在这里:https://leetcode.com/problems/number-of-ways-to-build-house-of-cards/description/
题目:
You are given an integer n representing the number of playing cards you have. A house of cards meets the following conditions:A house of cards consists…