POJ 3187  Backward Digit Sums http://poj.org/problem?id=3187 题目大意: 给你一个原始的数字序列: 3   1   2   4  他可以相邻的元素相加得到 4 3 6 然后 7 9 最后得到16,现在给定序列的长度,还有最后的得数,求原始序列(多解则取最小) 思路: 直接枚举即可. 下面是next_permutation版本. #include<cstdio> #include<cstdlib> #include<c…

题目:http://poj.org/problem?id=3187 题意: 像这样,输入N : 表示层数,输入over表示最后一层的数字,然后这是一个杨辉三角,根据这个公式,由最后一层的数,推出第一行的数字(由1~N组成).如果有多个解,按字典序升序,输出第一个解. 题解:水题,不多说 AC代码: #include <iostream> #include <cstdio> #include <cstdlib> #include <algorithm> usi…

Description FJ and his cows enjoy playing a mental game. They write down the numbers to N ( <= N <= ) ) might go like Behind FJ's back, the cows have started playing a more difficult game, in which they try to determine the starting sequence from on…

FJ and his cows enjoy playing a mental game. They write down the numbers from 1 to N (1 <= N <= 10) in a certain order and then sum adjacent numbers to produce a new list with one fewer number. They repeat this until only a single number is left. Fo…

暴力DFS+验证. 验证如果是暴力检验可能复杂度会太高,事实上可以o(1)进行,这个可以o(n*n)dp预处理. #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> using namespace std; ; bool flag[maxn]; bool r; int a[maxn]; int n,sum; ][]; bool check(int s) { ; ; }…

第1行j列的一个1加到最后1行满足杨辉三角,可以先推出组合数来 然后next_permutation直接暴. #include<cstdio> #include<iostream> #include <iterator> #include<string> #include<cstring> #include<queue> #include<vector> #include<stack> #include<…

-->Backward Digit Sums 直接写中文了 Descriptions: FJ 和 他的奶牛们在玩一个心理游戏.他们以某种方式写下1至N的数字(1<=N<=10). 然后把相邻的数相加的到新的一行数.重复这一操作直至只剩一个数字.比如下面是N=4时的一种例子 3 1 2 4 4 3 6 7 9 16 在FJ回来之前,奶牛们开始了一个更难的游戏:他们尝试根据最后结果找到开始的序列.这已超过了FJ的思考极限. 写一个程序来帮助FJ吧 Input N和最后的和 Output 满足…

Backward Digit Sums Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5495   Accepted: 3184 Description FJ and his cows enjoy playing a mental game. They write down the numbers from 1 to N (1 <= N <= 10) in a certain order and then sum ad…

POJ2718 Smallest Difference Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 6509   Accepted: 1773 Description Given a number of distinct decimal digits, you can form one integer by choosing a non-empty subset of these digits and writing…

A.Lake Counting(POJ 2386) 题意: 由于最近的降雨,农夫约翰田地的各个地方都有水汇聚,用N x M(1 <= N <= 100; 1 <= M <= 100)的矩形表示.每个方格包含水('W')或干燥土地('.').农夫约翰想弄清楚他的田地里形成了多少个池塘.池塘是一组相连的正方形,里面有水,其中一个正方形被认为与八个池塘相邻给定农夫约翰的田野图,确定他有多少个池塘. 思路: 染色法,移动可用(-1,0)类似数组,也可以用for循环,注意循环时递归可能会比在…