二分H2的位置,判断条件为是否有Hi < 0 #include <cstdio> #include <cstring> #include <cstdlib> #include <algorithm> #include <cmath> using namespace std; ; int N; double A; int dcmp( double a ) { ; ? - : ; } bool cal( double mid, double &…

POJ 1759 Garland  这个题wa了27次,忘了用一个数来储存f[n-1],每次由于二分都会改变f[n-1]的值,得到的有的值不精确,直接输出f[n-1]肯定有问题. 这个题用c++交可以过,g++交过不了, f[i]=2+2*f[i-1]-f[i-2]; f[0]=A,f[1]=x; 二分枚举x的值,最终得到B的值(不是f[n-1]), 上述递推式是非齐次的二阶递推式,解其齐次特征方程,可以得到f[n-1]的齐次时的表达式,对于非齐次的,目前我还没法求出通式, B与f[n-1]的关…

题目链接:http://poj.org/problem?id=1759 Garland Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 2477   Accepted: 1054 Description The New Year garland consists of N lamps attached to a common wire that hangs down on the ends to which outermo…

好吧  竟然因为编译器的问题不过  到底有什么区别 ???? 可以推出公式Hi = (i-1)H2 +(i-1)(i-2)-(i-2)*H1  因为所有的Hi都要大于零 Hn要最小 即存在Hi=0  即求H2可以达到的最大值 代入公式求出Hn #include <iostream> #include <cstdio> #include <algorithm> #define maxn 10010 using namespace std; int main() { int…

ural History Exam    二分 #include <iostream> #include <cstdlib> using namespace std; //二分查找 bool binarySearch(long a[], long x, int n){ ,right = n-; int middle; while (left <= right){ middle = (left+right)/; ; ; ; } ; } int cmp(const void *a…

[题目链接] http://poj.org/problem?id=1759 [题目大意] 有n个数字H,H[i]=(H[i-1]+H[i+1])/2-1,已知H[1],求最大H[n], 使得所有的H均大于0. [题解] 我们得到递推式子H[i]=2*H[i-1]+2-H[i-2],发现H[n]和H[2]成正相关 所以我们只要二分H[2]的取值,同时计算每个H是否大于等于0即可. [代码] #include <cstdio> int n; double H[1010],A,B; bool che…

During a discussion of problems at the Petrozavodsk Training Camp, Vova and Sasha argued about who of them could in 300 minutes find a pair of equal squares of the maximal size in a matrix of size N × M containing lowercase English letters. Squares c…

http://acm.hust.edu.cn/vjudge/contest/126149#problem/H 给定一条二次函数 f (x) = a * x * x + b * x + c 求一个最小的k,使得f(x) + f(x + 1) + f(x + 2) ..... + f(x + k - 1) 不等于 0 恒成立. 首先把参数统一写成 x + t这样的形式,然后带入去 化简有:a*x*x + (2*a*t+b)*x + a*t*t+b*t+c //现在的t是从0--k-1 列出k个式子,…

Description During a discussion of problems at the Petrozavodsk Training Camp, Vova and Sasha argued about who of them could in 300 minutes find a pair of equal squares of the maximal size in a matrix of size N × M containing lowercase English letter…

1822. Hugo II's War Time limit: 0.5 second Memory limit: 64 MB The glorious King Hugo II has declared a war-a war that is holy, victorious, almost bloodless, but ruinous! Right after declaring the war the king has started summoning the army. He plans…