代码随想录Day24

最新推荐文章于 2025-12-15 22:32:00 发布

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代码随想录Day24

LeetCode93.复原IP地址
LeetCode78.子集
LeetCode90.子集Ⅱ

LeetCode93.复原IP地址

class Solution {
public:
    vector<string> result;
    vector<string> restoreIpAddresses(string s) {
        dfs(s, 0, 0);
        return result;
    }
    bool judge(string s){
        for(int i = 0; i < s.length(); i++){
            if(s[i] > '9' || s[i] < '0')return false;
        }
        if(s == "0")return true;
        else if(s[0] > '0' && s[0] <= '9' && s.length() < 3)return true;
        else if(s.length() == 3 && s[0] < '2' && s[0] > '0')return true;
        else if(s.length() == 3 && s[0] == '2' && s[1] < '5' && s[1] >= '0')return true;
        else if(s.length() == 3 && s[0] == '2' && s[1] == '5' && s[2] >= '0' && s[2] <= '5')return true;
        return false;
    }
    void dfs(string s, int startindex, int times){
        if(times == 3){
            string sub_str = s.substr(startindex, s.length() - startindex);
            if(judge(sub_str)){
                result.push_back(s);
            }
        }
        else{
            for(int i = startindex + 1; i < s.length() && i <= startindex + 3; i++){
                string sub_str = s.substr(startindex, i - startindex);
                if(judge(sub_str)){
                    s.insert(i, ".");
                    dfs(s, i + 1, times + 1);
                    s.erase(i, 1);
                }
            }
        }
    }
};

LeetCode78.子集

class Solution {
public:
    vector<int> temp;
    vector<vector<int>> result;
    vector<vector<int>> subsets(vector<int>& nums) {
        result.push_back(temp);
        dfs(nums, 0, temp);
        return result;
    }
    void dfs(vector<int>& nums, int startIndex, vector<int>& path)
    {
        for(int i = startIndex; i < nums.size(); i++){
            path.push_back(nums[i]);
            result.push_back(path);
            dfs(nums, i + 1, path);
            path.pop_back();
        }
    }
};

LeetCode90.子集Ⅱ

class Solution {
public:
    vector<int> path;
    vector<vector<int>> result;
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        std::sort(nums.begin(),nums.end());
        vector<bool> used(nums.size(), false);
        result.push_back(path);
        dfs(nums, 0, path, used);
        return result;
    }
    void dfs(vector<int>& nums, int startIndex, vector<int>& path, vector<bool>& used){
        for(int i = startIndex; i < nums.size(); i++){
            if(i > 0 && used[i - 1] == true && nums[i] == nums[i - 1]){
                used[i - 1] = false;
                used[i] = true;
                continue;
            }
            path.push_back(nums[i]);
            result.push_back(path);
            used[i] = false;
            dfs(nums, i + 1, path, used);
            used[i] = true;
            path.pop_back();
        }
    }
};