1628: [Usaco2007 Demo]City skyline Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 256  Solved: 210[Submit][Status] Description The best part of the day for Farmer John's cows is when the sun sets. They can see the skyline of the distant city. Bessie w…

Description Input 第一行给出N,W 第二行到第N+1行:每行给出二个整数x,y,输入的x严格递增,并且第一个x总是1 Output 输出一个整数,表示城市中最少包含的建筑物数量 Sample Input 10 26 1 1 2 2 5 1 6 3 8 1 11 0 15 2 17 3 20 2 22 1 INPUT DETAILS: The case mentioned above Sample Output 6   题目的$w$没有意义 我们发现高度$h$出现一次时,答案+1…

http://www.lydsy.com/JudgeOnline/problem.php?id=1628 http://www.lydsy.com/JudgeOnline/problem.php?id=1683 又是重复的题.... 单调栈维护递减,然后相同的话矩形-1 #include <cstdio> #include <cstring> #include <cmath> #include <string> #include <iostream&g…

题目链接:http://www.lydsy.com/JudgeOnline/problem.php?id=1628 题意: 题解: 单调栈. 单调性: 栈内元素高度递增. 一旦出现比栈顶小的元素,则表明一栋房子的结束. 入栈: 如果出现了一个新的高度b(栈中没有),则入栈. 表明从现在开始,一定有一栋高度为b的房子,只是我们不知道它在哪里结束而已. 出栈: 对于现在的高度b,将栈中所有高度 > b的元素都出栈. 因为此时比b高的房子不得不结束. 每出栈一个元素,ans++. 注:最后要再多算一次…

还以为是dp呢 首先默认答案是n 对于一个影子,如果前边的影子比它高则可以归进前面的影子,高处的一段单算: 和他一样高的话就不用单算了,ans--: 否则入栈 #include<iostream> #include<cstdio> #include<algorithm> using namespace std; const int N=50005; int n,m,ans,top,h[N],s[N]; int read() { int r=0,f=1; char p=g…

1629: [Usaco2007 Demo]Cow Acrobats Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 601  Solved: 305[Submit][Status] Description Farmer John's N (1 <= N <= 50,000) cows (numbered 1..N) are planning to run away and join the circus. Their hoofed feet pre…

1645: [Usaco2007 Open]City Horizon 城市地平线 Time Limit: 5 Sec  Memory Limit: 64 MBSubmit: 315  Solved: 157[Submit][Status] Description Farmer John has taken his cows on a trip to the city! As the sun sets, the cows gaze at the city horizon and observe t…

BZOJ_1654_[Usaco2007 Open]City Horizon 城市地平线_扫描线 Description N个矩形块,交求面积并. Input * Line 1: A single integer: N * Lines 2..N+1: Input line i+1 describes building i with three space-separated integers: A_i, B_i, and H_i Output * Line 1: The total area,…

Max Increase to Keep City Skyline In a 2 dimensional array grid, each value grid[i][j] represents the height of a building located there. We are allowed to increase the height of any number of buildings, by any amount (the amounts can be different fo…

[BZOJ1630/2023][Usaco2007 Demo]Ant Counting 题意:T中蚂蚁,一共A只,同种蚂蚁认为是相同的,有一群蚂蚁要出行,个数不少于S,不大于B,求总方案数 题解:DP,先列出朴素的方程,用f[i][j]表示前i种,出行j只的方案数,v[i]代表第i中蚂蚁的个数 f[i][j]=∑f[i-1][j-k] (0≤k≤min(j,v[i])) 也可以表示为 f[i][j]=∑f[i-1][k] (j-min(j,v[i])≤k≤j) 发现时间复杂度为均摊O(A^2),…