LeetCode 40. Combination Sum II

LeetCode 40. Combination Sum II

Given acollection of candidate numbers (C) and a target number (T),find all unique combinations in C where the candidatenumbers sums to T.

Each numberin C may only be used once in thecombination.

Note:

• All numbers (including target) will be positive integers.
• The solution set must not contain duplicate combinations.

For example,given candidate set [10, 1, 2, 7, 6, 1, 5] andtarget 8, 
A solution set is: 

[

  [1,7],

  [1, 2, 5],

  [2,6],

  [1,1, 6]

]

Bfs深度优先科技解决，注意下可能会重复

比如这里我可以选第一个1和7 也可以选第二个1和7

 

 

代码：

class Solution {
public:
         vector<vector<int>>res;
         vector<vector<int>>combinationSum2(vector<int>& candidates,
                   inttarget) {
                   if(candidates.size() == 0) return res;
                   vector<int>ans(candidates.size());
                   sort(candidates.begin(),candidates.end());
                   bfs(candidates,0, ans, 0, target);
                   returnres;
         }
         voidbfs(vector<int>& candidates, int candidatesIndex,
                   vector<int>&ans, int ansIndex, int target) {
                  
                   if(target==0) {
                            vector<int>tmp(ans.begin(), ans.begin() + ansIndex);
                            res.push_back(tmp);
                            return;
                   }
                  
                   if(candidatesIndex >= candidates.size()||candidates[candidatesIndex] >target) return;
                   for(int i = candidatesIndex; i < candidates.size(); i++) {
                            if(i > candidatesIndex&&candidates[i] == candidates[i - 1]) continue;
                            ans[ansIndex]= candidates[i];
                            bfs(candidates,i + 1, ans, ansIndex + 1, target - candidates[i]);
                   }
         }
};