poj-1686-Lazy Math Instructor(stack)

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题目地址

http://poj.org/problem?id=1686

Code

#include <stdio.h>
#include <iostream>
#include <stdlib.h>
#include <string.h>
#include <queue>
#include <stack>
#include <string>
#include <map>
#include <sstream>
#include <vector>
#include <math.h>
#include <algorithm>
#define INF 0x3fffffff
#define N 1005
#define p(x) cout << (x) << endl;

int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};

using namespace std;
typedef long long LL;


int a[N];

int init[N];


int C(char a, char b){
    int r ;
    switch(b){
        case '+':
        case '-':
            if(a=='(' || a=='#')
                r = -1 ;    //入栈
            else
                r = 1 ;     //计算
            break ;
        case '*':
        case '/':
            if(a=='*' || a=='/' || a==')')
                r =1 ;      //计算
            else
                r = -1 ;    //入栈
            break ;
        case '(':
            if(a == ')'){
                printf("error!\n");
                exit(1) ;
            }
            else{
                r = -1 ;    //入栈
            }
            break ;
        case ')':
            if(a == '(')
                r = 0 ;
            else
                r = 1  ;
            break ;
        case '#':
            if(a=='#')
                r = 0 ;
            else
                r = 1 ;
            break ;
    }
    return r ;
}

int cal(int a, int b , char c){
    int res ;
    switch(c){
        case '+':   res = a + b ;   break ;
        case '-':   res = a - b ; break ;
        case '*':   res = a * b ; break ;
        case '/':   res = a / b ; break ;
    }
    //printf("%d = %d %c %d\n", res, a, c, b);
    return res ;
}


int hand(string s) {
    map<char, int> mp;

    for (int i = 0; i <= 9; i++) {
        mp['0'+i] = i;
    }

    int v = 1;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == ' ' || s[i] == '\t') {
            continue;
        }
        if (s[i] == '(' || s[i] == ')' || s[i] == '+' || s[i] == '-' || s[i] == '*') {
            continue;
        }
        if ('0' <= s[i] && s[i] <= '9') {
            continue;
        }
        // not same with 0~9
        if (mp[s[i]] == 0) {
            mp[s[i]] = s[i] - 'A' + 10;
        }
    }
    //p(mp['a'])
    //p(mp['b'])
    //p(mp['c'])
    //p(s)
    stack<char> f; f.push('#');
    stack<int> d;

    int x, y;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] == ' ' || s[i] == '\t') {
            continue;
        }
        char pre = f.top();
        char c = s[i];
        switch (c) {
            case '(' :
            case ')' :
            case '+' :
            case '-' :
            case '*' :
            case '#' :
                switch(C(pre, c)){
                    case 0:
                        f.pop();
                        break ;
                    case -1 :
                        f.push(c);
                        break ;
                    case 1 :
                        i--;
                        f.pop();
                        int a = d.top(); d.pop();
                        int b = d.top(); d.pop();
                        d.push(cal(b, a, pre));
                        break ;
                }
                break;
            default :  d.push(mp[c]); break;
        }
    }
    return d.top();
}

int main() {

#ifndef ONLINE_JUDGE
    freopen("in", "r", stdin);
#else
    //
#endif

    int n;
    cin >> n;
    getchar();
    for (int i = 0; i < n; i++) {
        string s1, s2;

        getline(cin, s1);
        getline(cin, s2);
        s1 += "#";
        s2 += "#";

        int ans1 = hand(s1);
        int ans2 = hand(s2);

        //cout << ans1 << " " << ans2 << endl;
        if (ans1 == ans2) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
    return 0;
}

参考

• http://blog.csdn.net/ivan_zjj/article/details/7354271