将木棒从大到小排列,保证每次的选择都是最长可选的木棒. 剪枝: 1 . 如果第 i 根木棒被选择却无法成功拼接,那么后面与其长度相同的也不能选择. 2 . 如果第 cnt + 1 根木棒无法成功拼接,就应该立即重构第 cnt 根木棒.那么如何判断是否能构造木棍呢?每次可以选择的最长木棒必须要选择,因为就算这次不选择,后面木棒的拼接也要用到该木棒,如果不能利用该木棍直接返回构造上一根木棍. 3 . 如果现在加入长度为x的一节木棒刚好组成一节完整的木棒,但是后面的木棍不能成功拼接,就重新选取上一节木…

题目链接:https://vjudge.net/problem/POJ-1011 题意:给定n(<=64)条木棍的长度(<=50),将这些木棍刚好拼成长度一样的若干条木棍,求拼出的可能的最小长度. 思路:经典的DFS剪枝题,这道题的剪枝技巧很关键. 数据不大,可以想到枚举木棍所有可能的长度,然后利用dfs来查找所有可能的搭配情况,dfs的参数len表示当前的木棍长度,rest表示还需要的长度,pos表示当前搜到的下标,num表示原始木棍中剩余没有匹配的数量,搜索的终止条件为rest==0&am…

Sticks Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 110416   Accepted: 25331 Description George took sticks of the same length and cut them randomly until all parts became at most 50 units long. Now he wants to return sticks to the or…

Sticks Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 129606   Accepted: 30388 Description George took sticks of the same length and cut them randomly until all parts became at most 50 units long. Now he wants to return sticks to the or…

Sticks Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 9779    Accepted Submission(s): 2907 Problem Description George took sticks of the same length and cut them randomly until all parts became…

POJ3009 DFS+剪枝 原题: Curling 2.0 Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 16280 Accepted: 6725 Description On Planet MM-21, after their Olympic games this year, curling is getting popular. But the rules are somewhat different from our…

ROADS Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 10777   Accepted: 3961 Description N cities named with numbers 1 ... N are connected with one-way roads. Each road has two parameters associated with it : the road length and the toll…

题目传送门 /* 题意:若干小木棍,是由多条相同长度的长木棍分割而成,问最小的原来长木棍的长度: DFS剪枝:剪枝搜索的好题!TLE好几次,终于剪枝完全! 剪枝主要在4和5:4 相同长度的木棍不再搜索:5 若新的搜索连第一条都没组合出来,直接break: 详细解释:http://blog.csdn.net/lyy289065406/article/details/6647960 http://www.cnblogs.com/devil-91/archive/2012/08/03/2621787.…

题目传送门 /* 题意:告诉一个区间[L,R],问根节点的n是多少 DFS+剪枝:父亲节点有四种情况:[l, r + len],[l, r + len - 1],[l - len, r],[l - len -1,r]; */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> #include <queue> using namespace std;…

Counting Cliques Time Limit: 8000/4000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 539    Accepted Submission(s): 204 Problem Description A clique is a complete graph, in which there is an edge between every pair…