Problem Description Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four different sums that equal 4: 4,3…

HDOJ(HDU).1258 Sum It Up (DFS) [从零开始DFS(6)] 点我挑战题目 从零开始DFS HDOJ.1342 Lotto [从零开始DFS(0)] - DFS思想与框架/双重DFS HDOJ.1010 Tempter of the Bone [从零开始DFS(1)] -DFS四向搜索/奇偶剪枝 HDOJ(HDU).1015 Safecracker [从零开始DFS(2)] -DFS四向搜索变种 HDOJ(HDU).1016 Prime Ring Problem (DF…

Sum It Up Problem Description Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four different sums that eq…

题意: 给一棵二叉树,每个叶子到根的路径之和为sum的,将所有可能的路径装进vector返回. 思路: 节点的值可能为负的.这样子就必须到了叶节点才能判断,而不能中途进行剪枝. /** * Definition for a binary tree node. * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL)…

题意: 在集合candidates中选出任意多个元素,使得他们的和为target,返回所有的组合,以升序排列. 思路: 难点在于如何去重,比如集合{1,1,2},target=3,那么只有一个组合就是1+2=3,而不是两个. DFS解决,每次考虑candidates[i]取还是不取,但是这样子还是会产生重复,这里只需要一个技巧就可以使得没有重复出现.如果当前元素已经被考虑过取了,那么在考虑不取的时候,i后面的与candidates[i]相同的都要跳过.观察一下可以发现,如果有一串相同的数字出现的…

题意: 在1-9这9个数字中选择k个出来,若他们的和为n,则加入答案序列,注意升序. 思路: 用DFS的方式,每次决定一个数字,共决策k次.假设上个决策是第i位为5,那么i+1位的范围就是6-9. class Solution { public: vector<vector<int>> combinationSum3(int k, int n) { vector<vector<int>> ans; vector<); DFS(ans,num,k,,,,…

题目大意:输入t,n,接下来有n个数组成的一个序列.输出总和为t的子序列 解题思路:DFS 代码如下(有详细的注释): #include <iostream> #include <algorithm> using namespace std; /** * t: 指定的和 * n: 给出的数的个数 * sign : 用来标记是否有解 * index :结果序列中元素的个数 * a[] :用来存储给出的数 * save[] :用来保存结果序列 * */ int t, n; int a[…

描述 One day,Tom’s girlfriend give him an array A which contains N integers and asked him:Can you choose some integers from the N integers and the sum of them is equal to K. 输入 There are multiple test cases. Each test ≤N≤),represents the array contains…

题目链接 Problem Description Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four different sums that equal 4…

Sum it up 题意:给定一个数sum,和n个数,求sum可以由这n个数里面的那几个数的和表示. Given a specified total t and a list of n integers, find all distinct sums using numbers from the list that add up to t. For example, if t=4, n=6, and the list is [4,3,2,2,1,1], then there are four d…