http://hihocoder.com/problemset/problem/1138 很久不用最短路,几乎连基本性质也忘了,结果这道题就是某些最短路算法空间复杂度是o(n) 这里总结四种算法 算法名称           时间复杂度       空间复杂度 dijkstra+heap  O(elog(e+n))   O(n) bellman-ford    O(ne)             O(n) spfa                O(ke)             O(n) fl…

题意,求1到n的最短路.不难想到单源最短路,难点在于数量级太大,因此如何建图是关键: 因为cost = min{|Xi-Xj|, |Yi-Yj|}:所以,点i的移动只有两种情况,. x距离最近的点,. y距离最近的点 如此一来,每个点i的最多只有四条边(为什么是四条?),这样复杂度就降下来了,单源最短路的复杂度为n*m(点*边数) 我用spfa. 解题思路: x轴排序,建图 y轴排序,建图 求最短路 用spfa注意队列que的大小至少是n*m,可以使用循环队列 #include <cstdio>…

Counting Islands II 描述 Country H is going to carry out a huge artificial islands project. The project region is divided into a 1000x1000 grid. The whole project will last for N weeks. Each week one unit area of sea will be filled with land. As a resu…

时间限制:10000ms 单点时限:1000ms 内存限制:256MB 描述 A company plans to recruit some new employees. There are N candidates (indexed from 1 to N) have taken the recruitment examination. After the examination, the well-estimated ability value as well as the expected…

#1578 : Visiting Peking University 时间限制:1000ms 单点时限:1000ms 内存限制:256MB 描述 Ming is going to travel for n days and the date of these days can be represented by n integers: 0, 1, 2, …, n-1. He plans to spend m consecutive days(2 ≤ m ≤ n)in Beijing. Durin…

题目描述 Farmer John has bought property in the Caribbean and is going to try to raise dairy cows on a big farm composed of islands. Set in his ways, he wants to surround all the islands with fence. Each island in the farm has the shape of a polygon. He…

A 2d grid map of m rows and n columns is initially filled with water. We may perform an addLand operation which turns the water at position (row, col) into a land. Given a list of positions to operate, count the number of islands after each addLand o…

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by…

hihocoder -1121-二分图的判定 1121 : 二分图一•二分图判定 时间限制:10000ms 单点时限:1000ms 内存限制:256MB 描述 大家好,我是小Hi和小Ho的小伙伴Nettle,从这个星期开始由我来完成我们的Weekly. 新年回家,又到了一年一度大龄剩男剩女的相亲时间.Nettle去姑姑家玩的时候看到了一张姑姑写的相亲情况表,上面都是姑姑介绍相亲的剩男剩女们.每行有2个名字,表示这两个人有一场相亲.由于姑姑年龄比较大了记性不是太好,加上相亲的人很多,所以姑姑一时也…

Hihocoder 太阁最新面经算法竞赛18 source: https://hihocoder.com/contest/hihointerview27/problems 题目1 : Big Plus 描述 Given an NxN 01 matrix, find the biggest plus (+) consisting of 1s in the matrix. size 1 plus size 2 plus size 3 plus size 4 plus 1 1 1 1 111 1 1…