752. 打开转盘锁

链接:

752. 打开转盘锁

题解:

cpp 复制代码
class Solution {
public:
    int openLock(vector<string>& deadends, string target) {
        std::unordered_set<std::string> table(deadends.begin(), deadends.end());
        if (table.find("0000") != table.end()
                || table.find(target) != table.end()) {
            return -1;
        }
        std::queue<std::string> que;
        std::unordered_map<std::string, int> distance;
        que.push(std::string("0000"));
        distance["0000"] = 0;
        auto get_next = [](std::string& word)->std::vector<std::string> {
            std::vector<std::string> result;
            for (int i = 0; i < word.size(); ++i) {
                char ch = word[i];
                if (word[i] == '9') {
                    word[i] = '0';
                } else {
                    ++word[i];
                }
                result.push_back(word);
                word[i] = ch;
                if (word[i] == '0') {
                    word[i] = '9';
                } else {
                    --word[i];
                }
                result.push_back(word);
                word[i] = ch;
            }
            return result;
        };
        while (!que.empty()) {
            int size = que.size();
            for (int i = 0; i < size; ++i) {
                auto f = que.front();
                que.pop();
                if (f == target) {
                    return distance[f];
                }
                for (auto& next : get_next(f)) {
                    //cout << "next = " << next << endl;
                    if (table.find(next) != table.end()) {
                        continue;
                    }
                    if (distance.find(next) != distance.end()) {
                        continue;
                    }
                    /*if (next == target) {
                        return distance[f] + 1;
                    }*/
                    distance[next] = distance[f] + 1;
                    que.push(next);
                }
            }
        }
        return -1;
    }
};
cpp 复制代码
class Solution {
public:
    int openLock(vector<string>& deadends, string target) {
        if (target == "0000") {
            return 0;
        }

        unordered_set<string> dead(deadends.begin(), deadends.end());
        if (dead.count("0000")) {
            return -1;
        }

        auto num_prev = [](char x) -> char {
            return (x == '0' ? '9' : x - 1);
        };
        auto num_succ = [](char x) -> char {
            return (x == '9' ? '0' : x + 1);
        };

        // 枚举 status 通过一次旋转得到的数字
        auto get = [&](string& status) -> vector<string> {
            vector<string> ret;
            string bak = status;
            for (int i = 0; i < 4; ++i) {
                char num = status[i];
                status[i] = num_prev(num);
                ret.push_back(status);
                status[i] = num_succ(num);
                ret.push_back(status);
                status = bak;
            }
            return ret;
        };

        queue<pair<string, int>> q;
        q.emplace("0000", 0);
        unordered_set<string> seen = {"0000"};
        int step = 0;
        while (!q.empty()) {
            auto [status, step] = q.front();
            q.pop();
            for (auto&& next_status: get(status)) {
                if (!seen.count(next_status) && !dead.count(next_status)) {
                    if (next_status == target) {
                        //return step + 1;
                        return step+1;
                    }
                    q.emplace(next_status, step + 1);
                    seen.insert(move(next_status));
                }
               
            }
            ++step;
        }

        return -1;
    }
};
相关推荐
CoovallyAIHub7 小时前
中科大DSAI Lab团队多篇论文入选ICCV 2025,推动三维视觉与泛化感知技术突破
深度学习·算法·计算机视觉
NAGNIP8 小时前
Serverless 架构下的大模型框架落地实践
算法·架构
moonlifesudo8 小时前
半开区间和开区间的两个二分模版
算法
moonlifesudo8 小时前
300:最长递增子序列
算法
CoovallyAIHub13 小时前
港大&字节重磅发布DanceGRPO:突破视觉生成RLHF瓶颈,多项任务性能提升超180%!
深度学习·算法·计算机视觉
CoovallyAIHub13 小时前
英伟达ViPE重磅发布!解决3D感知难题,SLAM+深度学习完美融合(附带数据集下载地址)
深度学习·算法·计算机视觉
聚客AI1 天前
🙋‍♀️Transformer训练与推理全流程:从输入处理到输出生成
人工智能·算法·llm
大怪v1 天前
前端:人工智能?我也会啊!来个花活,😎😎😎“自动驾驶”整起!
前端·javascript·算法
惯导马工1 天前
【论文导读】ORB-SLAM3:An Accurate Open-Source Library for Visual, Visual-Inertial and
深度学习·算法
骑自行车的码农2 天前
【React用到的一些算法】游标和栈
算法·react.js