代码随想录算法训练营第29天| 491.递增子序列 46.全排列 47.全排列 II

• 今日学习的文章链接，或者视频链接

第七章 回溯算法part05

• 自己看到题目的第一想法

• 看完代码随想录之后的想法

491

class Solution {
public:
    vector> result;
    vector path;
    void backtracking(vector& nums,int startIndex){
        if(path.size()>=2){
            result.push_back(path);
        }
        std::set prev;
        prev.clear();
        for(int i = startIndex;i= path.back()){
                path.push_back(nums[i]);
                prev.insert(nums[i]);
                backtracking(nums, i + 1);
                path.pop_back();
            }
        }
    }
    vector> findSubsequences(vector& nums) {
        //sort(nums.begin(),nums.end());
        backtracking(nums,0);
        return result;
    }
};

46

class Solution {
public:
    vector> result;
    vector path;
    void backtracking(vector& nums){
        if(path.size()==nums.size()){
            result.push_back(path);
        }
        for(int i = 0;i> permute(vector& nums) {
        backtracking(nums);
        return result;
    }
};

47

class Solution {
public:
    vector> result;
    vector path;
    void backtracking(vector& nums,vector& used){
        if(path.size()==nums.size()){
            result.push_back(path);
            return;
        }
        for (int i = 0 ; i0&&nums[i]==nums[i-1]&&used[i-1]==false) continue;
            path.push_back(nums[i]);
            used[i] = true;
            backtracking(nums,used);
            path.pop_back();
            used[i] = false;
        }
    }
    vector> permuteUnique(vector& nums) {
        sort(nums.begin(),nums.end());
        vector used(nums.size(), false);
        backtracking(nums,used);
        return result;
    }
};

• 自己实现过程中遇到哪些困难

• 今日收获，记录一下自己的学习时长