leetcode/problems-cpp/parse-lisp-expression/solution.h at main · goodstudyqaq/leetcode · GitHub

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/*
Code generated by https://github.com/goodstudyqaq/leetcode-local-tester
*/
#if __has_include("../utils/cpp/help.hpp")
#include "../utils/cpp/help.hpp"
#elif __has_include("../../utils/cpp/help.hpp")
#include "../../utils/cpp/help.hpp"
#else
#define debug(...) 42
#endif

class Solution {
   public:
    int evaluate(string s) {
        int now = 0;
        int n = s.size();
        function<int(map<string, int> value)> dfs = [&](map<string, int> value) -> int {
            debug(now, value);
            // s[now] must be (
            if (s[now + 1] == 'a' || s[now + 1] == 'm') {
                // add
                bool is_add = (s[now + 1] == 'a');
                now += 5;
                if (!is_add) now++;
                vector<int> v;
                for (int i = 0; i < 2; i++) {
                    if (s[now] == '(') {
                        int tmp = dfs(value);
                        if (i == 0) {
                            now++;
                        }
                        v.push_back(tmp);
                    } else {
                        // name or number
                        if (s[now] >= 'a' && s[now] <= 'z') {
                            string name = "";
                            while ((s[now] >= 'a' && s[now] <= 'z') || (s[now] >= '0' && s[now] <= '9')) {
                                name += s[now];
                                now++;
                            }
                            v.push_back(value[name]);
                        } else {
                            int flag = 1;
                            if (s[now] == '-') flag = -1, now++;
                            int val = 0;
                            while (s[now] >= '0' && s[now] <= '9') val = val * 10 + s[now] - '0', now++;
                            v.push_back(val * flag);
                        }

                        if (i == 0) {
                            now++;
                        }
                    }
                }
                now++;
                debug(v);
                if (is_add)
                    return v[0] + v[1];
                else
                    return v[0] * v[1];
            } else {
                // let
                now += 5;
                while (true) {
                    if (s[now] == '(') {
                        int val = dfs(value);
                        now++;
                        return val;
                    } else if (s[now] >= 'a' && s[now] <= 'z') {
                        string name;
                        while ((s[now] >= 'a' && s[now] <= 'z') || (s[now] >= '0' && s[now] <= '9')) {
                            name += s[now];
                            now++;
                        }
                        if (s[now] == ')') {
                            int res = value[name];
                            now++;
                            return res;
                        }
                        now++;
                        if (s[now] == '(') {
                            int val = dfs(value);
                            value[name] = val;
                        } else if ((s[now] >= '0' && s[now] <= '9') || s[now] == '-') {
                            int val = 0;
                            int flag = 1;
                            if (s[now] == '-') flag = -1, now++;
                            while (s[now] >= '0' && s[now] <= '9') val = val * 10 + s[now] - '0', now++;
                            value[name] = val * flag;
                        } else {
                            string name2 = "";
                            while ((s[now] >= 'a' && s[now] <= 'z') || (s[now] >= '0' && s[now] <= '9')) {
                                name2 += s[now];
                                now++;
                            }
                            value[name] = value[name2];
                        }
                        now++;
                    } else if ((s[now] >= '0' && s[now] <= '9') || s[now] == '-') {
                        int flag = 1;
                        if (s[now] == '-') flag = -1, now++;
                        int val = 0;
                        while (s[now] >= '0' && s[now] <= '9') val = val * 10 + s[now] - '0', now++;
                        now++;
                        return val * flag;
                    }
                }
            }
        };
        return dfs({});
    }
};