BUAA 623 Chem is Try！

http://oj55.bianchengla.com/problem/623/

　　好久没写过题解了，昨天做了一道挺恶心的题目，贴一下代码上来。看了一下提交状况，好像我的代码挺短的了，至少我找不到比我短的代码。RE1，AC。

代码如下：

 #include <cctype>
 #include <cstdio>
 #include <cstring>
 #include <map>
 #include <string>
 #include <iostream>
 #include <algorithm>

 using namespace std;

 const int N = ;
 char buf[N], *p[];
 typedef long long LL;
 typedef map<string, LL> MSL;
 #define x first
 #define y second

 string get_s(int x) {
     string ret = "";
     ret += *(p[x]++);
     while (islower(*p[x])) ret += *p[x], p[x]++;
     return ret;
 }

 int get_d(int x) {
     int ret = ;
     while (isdigit(*p[x])) ret = ret *  + *p[x] - '', p[x]++;
     return ret;
 }

 MSL merge(MSL a, MSL b) {
     MSL c;
     for (MSL::iterator mi = a.begin(); mi != a.end(); mi++) c[mi->x] += mi->y;
     for (MSL::iterator mi = b.begin(); mi != b.end(); mi++) c[mi->x] += mi->y;
     return c;
 }

 void print(MSL &a) { for (MSL::iterator mi = a.begin(); mi != a.end(); mi++) cout << mi->x << '~' << mi->y << ' '; cout << endl; }
 void multiply(MSL &a, LL p) { for (MSL::iterator mi = a.begin(); mi != a.end(); mi++) mi->y *= p; }

 MSL dfs(int x, char end) {
     MSL cur;
     //cout << x << ' ' << p[x] << endl;
     while (*p[x] && *p[x] != end && *p[x] != ')') {
         //cout << x << ' ' << *p[x] << endl;
         if (*p[x] == '+') { p[x]++; continue; }
         if (isdigit(*p[x])) {
             int t = get_d(x);
             MSL tmp = dfs(x, '+');
             multiply(tmp, t);
             cur = merge(cur, tmp);
         } else {
             if (*p[x] == '(') {
                 p[x]++; MSL tmp = dfs(x, ')');
                 if (*p[x] == ')') p[x]++;
                 if (isdigit(*p[x])) multiply(tmp, get_d(x));
                 cur = merge(cur, tmp);
             } else {
                 string s = get_s(x);
                 if (isdigit(*p[x])) cur[s] += get_d(x);
                 else cur[s]++;
             }
         }
     }
     return cur;
 }

 int main() {
     //freopen("in", "r", stdin);
     while (~scanf("%s", buf)) {
         p[] = p[] = buf;
         while (*p[] != '=') p[]++; *(p[]++) = ;
         MSL ans1, ans2, tmp;
         while () {
             tmp = dfs(, '+');
             ans1 = merge(ans1, tmp);
             if (*p[] == ) break;
             p[]++;
             //cout << p[0] << endl;
         }
         while () {
             tmp = dfs(, '+');
             ans2 = merge(ans2, tmp);
             if (*p[] == ) break;
             p[]++;
             //cout << p[1] << endl;
         }
         MSL::iterator m1 = ans1.begin(), m2 = ans2.begin();
         //print(ans1); print(ans2);
         while () {
             if (m1 == ans1.end()) break;
             if (m2 == ans2.end()) break;
             if (*m1 != *m2) break;
             m1++, m2++;
         }
         m1 == ans1.end() && m2 == ans2.end() ? puts("YES") : puts("NO");
     }
     return ;
 }

——written by Lyon