代码里有注释。。。直接上代码。。。

#include
    
     #define rep(i,k,n) for(int i=k;i<=n;i++)#define per(i,n,k) for(int i=n;i>=k;i--)#define pii pair
     
      #define pb push_back#define mp make_pair#define re return#define se second#define fi firstusing namespace std;//---------------------------------------------------------------head----------------------------------------------------------------------struct BigInteger {    typedef unsigned long long LL;    static const int BASE = 100000000;    static const int WIDTH = 8;    vector
      
        s;    BigInteger& clean(){while(!s.back()&&s.size()>1)s.pop_back(); return *this;}    BigInteger(LL num = 0) {*this = num;}    BigInteger(string s) {*this = s;}    BigInteger& operator = (long long num) {        s.clear();        do {            s.push_back(num % BASE);            num /= BASE;        } while (num > 0);        return *this;    }    BigInteger& operator = (const string& str) {        s.clear();        int x, len = (str.length() - 1) / WIDTH + 1;        for (int i = 0; i < len; i++) {            int end = str.length() - i*WIDTH;            int start = max(0, end - WIDTH);            sscanf(str.substr(start,end-start).c_str(), "%d", &x);            s.push_back(x);        }        return (*this).clean();    }    BigInteger operator + (const BigInteger& b) const {        BigInteger c; c.s.clear();        for (int i = 0, g = 0; ; i++) {            if (g == 0 && i >= s.size() && i >= b.s.size()) break;            int x = g;            if (i < s.size()) x += s[i];            if (i < b.s.size()) x += b.s[i];            c.s.push_back(x % BASE);            g = x / BASE;        }        return c;    }    BigInteger operator - (const BigInteger& b) const {        assert(b <= *this); // 减数不能大于被减数        BigInteger c; c.s.clear();        for (int i = 0, g = 0; ; i++) {            if (g == 0 && i >= s.size() && i >= b.s.size()) break;            int x = s[i] + g;            if (i < b.s.size()) x -= b.s[i];            if (x < 0) {g = -1; x += BASE;} else g = 0;            c.s.push_back(x);        }        return c.clean();    }    BigInteger operator * (const BigInteger& b) const {        int i, j; LL g;        vector
       
         v(s.size()+b.s.size(), 0);        BigInteger c; c.s.clear();        for(i=0;i
        
         = v.size()) break;            LL x = v[i] + g;            c.s.push_back(x % BASE);            g = x / BASE;        }        return c.clean();    }    BigInteger operator / (const BigInteger& b) const {        assert(b > 0);  // 除数必须大于0        BigInteger c = *this;       // 商:主要是让c.s和(*this).s的vector一样大        BigInteger m;               // 余数:初始化为0        for (int i = s.size()-1; i >= 0; i--) {            m = m*BASE + s[i];            c.s[i] = bsearch(b, m);            m -= b*c.s[i];        }        return c.clean();    }    BigInteger operator % (const BigInteger& b) const { //方法与除法相同        BigInteger c = *this;        BigInteger m;        for (int i = s.size()-1; i >= 0; i--) {            m = m*BASE + s[i];            c.s[i] = bsearch(b, m);            m -= b*c.s[i];        }        return m;    }    int bsearch(const BigInteger& b, const BigInteger& m) const{        int L = 0, R = BASE-1, x;        while (1) {            x = (L+R)>>1;            if (b*x<=m) {if (b*(x+1)>m) return x; else L = x;}            else R = x;        }    }    BigInteger& operator += (const BigInteger& b) {*this = *this + b; return *this;}    BigInteger& operator -= (const BigInteger& b) {*this = *this - b; return *this;}    BigInteger& operator *= (const BigInteger& b) {*this = *this * b; return *this;}    BigInteger& operator /= (const BigInteger& b) {*this = *this / b; return *this;}    BigInteger& operator %= (const BigInteger& b) {*this = *this % b; return *this;}    bool operator < (const BigInteger& b) const {        if (s.size() != b.s.size()) return s.size() < b.s.size();        for (int i = s.size()-1; i >= 0; i--)            if (s[i] != b.s[i]) return s[i] < b.s[i];        return false;    }    bool operator >(const BigInteger& b) const{return b < *this;}    bool operator<=(const BigInteger& b) const{return !(b < *this);}    bool operator>=(const BigInteger& b) const{return !(*this < b);}    bool operator!=(const BigInteger& b) const{return b < *this || *this < b;}    bool operator==(const BigInteger& b) const{return !(b < *this) && !(b > *this);}};ostream& operator << (ostream& out, const BigInteger& x) {    out << x.s.back();    for (int i = x.s.size()-2; i >= 0; i--) {        char buf[20];        sprintf(buf, "%08d", x.s[i]);        for (int j = 0; j < strlen(buf); j++) out << buf[j];    }    return out;}istream& operator >> (istream& in, BigInteger& x) {    string s;    if (!(in >> s)) return in;    x = s;    return in;}stack
         
           si;stack
          
            sc;vector
           
             vc;bool isnum[1005];bool flag=0;BigInteger pow(BigInteger a,BigInteger b){BigInteger base=a,ans=1;while(b!=0){if(b%2==1)ans*=base;base*=base;b/=2;}return ans;}BigInteger clas(char c)//符号优先级 { if(c=='(' || c==')') re 0; if(c=='+' || c=='-') re 1; if(c=='*' || c=='/') re 2; if(c=='^') re 3; re 4;}BigInteger cal(BigInteger a,BigInteger b,BigInteger c)//符号求值 { BigInteger ans=1; if(c=='+') re a+b; if(c=='-') re b-a; if(c=='*') re a*b; if(c=='/') re b/a; re pow(b,a);}int main(){ string s;cin>>s; s="("+s+")";//可以用来防止栈为空找top时的溢出情况 int n=(int)s.size(); rep(i,0,n-1) { if(s[i]=='(')//左括号直接压入 { sc.push(s[i]); continue; } if(s[i]==')')//找到右括号将栈清空到左括号为止 { char c=sc.top();sc.pop(); while(c!='(') { vc.pb(c); c=sc.top();sc.pop(); } continue; } if(s[i]>='0' && s[i]<='9')//数字 { BigInteger sum=0; while(s[i]>='0' && s[i]<='9') sum=sum*10+s[i++]-'0'; if(flag) sum=BigInteger(-1)*sum,flag=0; vc.pb(sum); isnum[vc.size()-1]=1; i--;continue; } if(s[i]=='-' && (clas(s[i-1])!=4 && s[i-1]!=')')) { flag=1; continue; } while(!sc.empty() && clas(s[i])<=clas(sc.top()))//如果是符号就找到第一个优先级比他小的 vc.pb(sc.top()),sc.pop(); sc.push(s[i]); } while(!sc.empty())//清空栈 vc.pb(sc.top()),sc.pop(); rep(i,0,vc.size()-1)//根据后缀表达式求值 { if(!isnum[i]) { BigInteger a=si.top();si.pop(); BigInteger b=si.top();si.pop(); BigInteger ans=cal(a,b,vc[i]); si.push(ans); } else si.push(vc[i]); } cout<