[Leetcode] 039. Combination Sum (Medium) (c + +)

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Github:https://github.com/illuz/leetcode

039. Combination Sum (Medium) links：

Title: https://leetcode.com/problems/combination-sum/
Code (GitHub): Https://github.com/illuz/leetcode

Test Instructions：

Given a set of positive integers, and a target number, select some numbers from the set so that they are equal to the number of targets and can be repeated to select the number in the collection.
The collection of the resulting solutions cannot have duplicates.

Analysis：

Violent search used to be possible, first ordered, and then with DFS, each time there are two options, one is to select the current number and then recursive current number, the second is not to select the current number of direct recursion under the number.
This question is very good for understanding DFS.

Code: (c + +)

/** Author:illuz <iilluzen[at]gmail.com>* file:ac_dfs_n!. cpp* Create date:2015-01-01 10:45:58* Descripton:dfs, choose or not choose*/#include <bits/stdc++.h>using names  Pace Std;const int N = 0;class Solution {private:void dfs (vector<vector<int> > &ans, vector<int>        &single, vector<int> &candi, int cur, int rest) {int sz = candi.size ();        if (sz <= cur | | Rest < 0) return;            if (rest = = 0) {ans.push_back (single);        Return        }//Choose cur single.push_back (candi[cur]);        DFS (ans, single, Candi, cur, rest-candi[cur]);        Single.pop_back ();    Don ' t choose Cur dfs (ans, single, Candi, cur + 1, rest); }public:vector<vector<int> > Combinationsum (vector<int> &candidates, int target) {vector        <vector<int> > ans;        Vector<int> single; Sort (candidates. Begin (), Candidates.end ());        DFS (ans, single, candidates, 0, target);    return ans;    }};int Main () {int tar;    int n;    Solution S;    CIN >> n >> Tar;    Vector<int> v (n);    for (int i = 0; i < n; i++) cin >> V[i];    vector<vector<int> > Res = s.combinationsum (v, tar);        for (auto &i:res) {for (auto &j:i) cout << J << ';    Puts (""); } return 0;}

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[Leetcode] 039. Combination Sum (Medium) (c + +)