Description Every year the cows hold an event featuring a peculiar version of hopscotch that involves carefully jumping from rock to rock in a river. The excitement takes place on a long, straight river with a rock at the start and another rock at th…

1650: [Usaco2006 Dec]River Hopscotch 跳石子 Time Limit: 5 Sec  Memory Limit: 64 MB Description Every year the cows hold an event featuring a peculiar version of hopscotch that involves carefully jumping from rock to rock in a river. The excitement takes…

http://www.lydsy.com/JudgeOnline/problem.php?id=1650 看到数据和最小最大时一眼就是二分... 但是仔细想想好像判断时不能贪心? 然后看题解还真是贪心..囧. 原来是之前我脑残了. ... 贪心很简单 排序后. 当前点到之前的点的距离<m就累计(相当于删掉这个点,为什么呢?因为这个点假设last到的不是0,那么这个点删了后,因为后边的点的距离大于它,假设后边的点距离减去这个点的距离也是<m,那么显然删去这个点可以得到2个不用删去的点(否则一定要…

题目链接:http://www.lydsy.com/JudgeOnline/problem.php?id=1650 题意: 数轴上有n个石子,第i个石头的坐标为Di,现在要从0跳到L,每次条都从一个石子跳到相邻的下一个石子. 现在FJ允许你移走M个石子,问移走这M个石子后,相邻两个石子距离的最小值的最大值是多少. 题解: 二分. check函数: (1)求出每个区间的长度len[i] = dis[i+1] - dis[i]. (2)对于第1到n-1个区间,如果len[i] > now,则去掉右端…

脑子一抽写了个堆,发现不对才想起来最值用二分 然后判断的时候贪心的把不合mid的区间打通,看打通次数是否小于等于m即可 #include<iostream> #include<cstdio> #include<algorithm> using namespace std; const int N=50005; int L,n,m,a[N]; int read() { int r=0,f=1; char p=getchar(); while(p>'9'||p<…

P2855 [USACO06DEC]河跳房子River Hopscotch 二分+贪心 每次二分最小长度,蓝后检查需要去掉的石子数是否超过限制. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; #define N 50010 int n,m,L,a[N]; bool check(int lim){ ; ,j=;i<…

River Hopscotch Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 11031   Accepted: 4737 Description Every year the cows hold an event featuring a peculiar version of hopscotch that involves carefully jumping from rock to rock in a river.…

POJ3285 River Hopscotch 此题是大白P142页(即POJ2456)的一个变形题,典型的最大化最小值问题. C(x)表示要求的最小距离为X时,此时需要删除的石子.二分枚举X,直到找到最大的X,由于c(x)=m时满足题意,所以最后输出的是ub-1或者lb(lb==ub-1 注意相邻距离小于x的要删除(此处不是小于等于),对于相邻的距离小于x的两个石子,当删除其中一个后,又会产生其他的相邻的石子,直接计数不好计数,不妨用两个标记last,cur,其中last表示上一个石子,cur…

River Hopscotch Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 9923   Accepted: 4252 Description Every year the cows hold an event featuring a peculiar version of hopscotch that involves carefully jumping from rock to rock in a river. T…

1648: [Usaco2006 Dec]Cow Picnic 奶牛野餐 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 432  Solved: 270[Submit][Status] Description The cows are having a picnic! Each of Farmer John's K (1 <= K <= 100) cows is grazing in one of N (1 <= N <= 1,000)…