C++ DFS class Solution { public: void help(vector<int> &a, int now, int sum, int target, vector<int> &path, vector<vector<int> > &ans, bool last) { if (sum > target) { return ; } if (now >= a.size()) { if (sum ==…

一个数可以使用多次 图: 节点:x(当前的和,当前要考虑的数a[i]) 边:x-> y1(当前的和,下一个要考虑的数a[i+1]) y2(当前的和+a[i],下一个要考虑的数a[i+1]) BFS 如何求具体解? 队列里放全部的“部分解”——浪费空间 每个节点存放到它的前一个节点——最终还要计算解 DFS 会好一些 leetcode 77,78,90:枚举全部子集 leetcode 51,52:n皇后问题 class Solution { public: void help(vector<in…

Given an integer array with all positive numbers and no duplicates, find the number of possible combinations that add up to a positive integer target. Example: nums = [1, 2, 3] target = 4 The possible combination ways are: (1, 1, 1, 1) (1, 1, 2) (1,…

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1…

Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combination. Note: All numbers (including target) will be posi…

Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (including target) will…

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. Ensure that numbers within the set are sorted in ascending order. Example 1…

Combination Sum Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (includi…

Combination Sum | Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. For example, given candi…

Combination Sum II Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combination. Note: All numbers (including t…