每次到达一个点,或者点亮一个房间的灯的时候,检查一下它四周的点能否走. 一开始看错题了..要求的是最多能开多少房的灯. #include<cstdio> #include<iostream> #include<cstring> #include<cmath> #include<algorithm> using namespace std; ; ]={,,,-},yy[]={,-,,}; ];int tot,last[maxn]; int dlx[…

bzoj4395[Usaco2015 dec]Switching on the Lights 题意: n*n个房间,奶牛初始在(1,1),且只能在亮的房间里活动.每当奶牛经过一个房间,就可以打开这个房间里控制其它房间灯的开关.问奶牛最多可点亮多少个房间.n≤100. 题解: 因为只要一个房间灯亮了,它将一直亮着,所以可以做bfs,每次由队列中的节点扩展可以到的节点.然而这样做不行,因为可能之前尝试过不能到达的房间的灯可以在之后到达的房间里被打开.解决方法是不停做bfs,直到答案不再更新. 代码:…

4390: [Usaco2015 dec]Max Flow Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 177  Solved: 113[Submit][Status][Discuss] Description Farmer John has installed a new system of N−1 pipes to transport milk between the N stalls in his barn (2≤N≤50,000), c…

[BZOJ4391][Usaco2015 dec]High Card Low Card(贪心) 题面 BZOJ 题解 预处理前缀后缀的结果,中间找个地方合并就好了. #include<iostream> #include<cstdio> #include<cstdlib> #include<cstring> #include<cmath> #include<algorithm> #include<set> using na…

4397: [Usaco2015 dec]Breed Counting Time Limit: 10 Sec  Memory Limit: 128 MB Description Farmer John's N cows, conveniently numbered 1…N, are all standing in a row (they seem to do so often that it now takes very little prompting from Farmer John to…

[Usaco2015 dec]Max Flow Time Limit: 10 Sec  Memory Limit: 128 MBSubmit: 353  Solved: 236[Submit][Status][Discuss] Description Farmer John has installed a new system of N−1 pipes to transport milk between the N stalls in his barn (2≤N≤50,000), conveni…

P2845 [USACO15DEC]Switching on the Lights 开关灯 题目背景 来源:usaco-2015-dec Farm John 最近新建了一批巨大的牛棚.这些牛棚构成了一个N*N的矩形网络.(1<n<100) 然而bessie十分怕黑,他想计算可以把多少个牛棚的灯打开. 题目描述 有NN个房间,组成了一张NN的网格图,Bessie一开始位于左上角(1,1),并且只能上下左右行走. 一开始,只有(1,1)这个房间的灯是亮着的,Bessie只能在亮着灯的房间里活动.…

P2828 Switching on the Lights(开关灯) 题目背景 来源:usaco-2015-dec Farm John 最近新建了一批巨大的牛棚.这些牛棚构成了一个N*N的矩形网络.(1<n<100) 然而bessie十分怕黑,他想计算可以把多少个牛棚的灯打开. 题目描述 有N*N个房间,组成了一张N*N的网格图,Bessie一开始位于左上角(1,1),并且只能上下左右行走. 一开始,只有(1,1)这个房间的灯是亮着的,Bessie只能在亮着灯的房间里活动. 有另外M条信息,每…

题意: T,A,B.T是上限.A和B可以随意吃但是不能超过T.有一次将吃的东西/2的机会.然后可以继续吃,不能超过T.问最多可以吃多少. =>我们先处理不能/2可以吃到哪些.然后弄个双指针扫一扫就可以了TAT #include<cstdio> #include<cstring> #include<cctype> #include<algorithm> using namespace std; #define rep(i,s,t) for(int i=s…

BZOJ4390: [Usaco2015 dec]Max Flow Description Farmer John has installed a new system of N−1 pipes to transport milk between the N stalls in his barn (2≤N≤50,000), conveniently numbered 1…N. Each pipe connects a pair of stalls, and all stalls are conn…