王道机试指南5.1~5.3向量，队列，栈

例题5.1完数和盈数（清华大学复试上机）

#include<iostream>
#include<cstdio>
#include<vector>
using namespace std;
int sum(int n){
    int sum0 = 0;
    for(int i = 1; i < n; i++){
        if(n % i == 0) sum0 += i;
    }
    return sum0;
}
int main(){
    vector<int> a, b;
    for(int i = 2; i < 61; i++){
        if(sum(i) == i) a.push_back(i);
        if(sum(i) > i) b.push_back(i);
    }
    cout << "E :";
    for(int i = 0; i < a.size(); i++)
        cout << a[i] << " ";
    cout << "G :";
    for(int i = 0; i < b.size(); i++)
        cout << b[i] << " ";
}  

例题5.4 Zero-complexity Transposition(上海交通大学上机）

#include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
int main(){
    int n;
    cin >> n; 
    stack<long long> s;
    for(int i = 0; i < n; i++){
        int temp;
        cin >> temp;
        s.push(temp);
    }
    for(int i = 0; i < n; i++){
        cout << s.top() << " ";
        s.pop();
    }
    return 0;
}  

例题5.6简单计算器（浙江大学上机）

#include<iostream>
#include<cstdio>
#include<string>
#include<stack>
#include<cctype>
using namespace std;
int priority(char c){
    if(c == '#') {
        return 0;
    }else if(c == '$'){
        return 1;
    } else if(c == '+' || c == '-'){
        return 2;
    }else{
        return 3;
    }
}
double getnumber(string s, int& index){
    double number = 0;
    while(isdigit(s[index])){
        number = number * 10 + s[index] - '0';
        index ++;
    }
    return number;
}
double cal(double x, double y, char op){
    double result = 0;
    if(op == '+') result =  x + y;
    if(op == '-') result =  x - y;
    if(op == '*') result =  x * y;
    if(op == '/') result =  x / y;
    return result;
}
int main(){
    string s;
    while(getline(cin, s)){
        if(s == "0") break;
        int index = 0;
        stack<double> data;
        stack<char> oper;
        s += '$';
        oper.push('#');
        while(index < s.size() ){
            if(s[index] == ' '){
                index ++;
            }else if(isdigit(s[index])){
                data.push(getnumber(s, index));
            }else{
                if(priority(oper.top()) < priority(s[index])){
                    oper.push(s[index]);
                    index ++;
                }else{
                    double y = data.top();
                    data.pop();
                    double x = data.top();
                    data.pop();
                    data.push(cal(x, y, oper.top()));
                    oper.pop();
                }
            }
        }
        printf("%.2f\n", data.top());
    }
    return 0;
}  

习题5.1堆栈的使用（吉林大学上机）

#include<iostream>
#include<cstdio>
#include<stack>
using namespace std;
int main(){
    int n;
    while(cin >> n){
        if(n == 0) break;
        stack <int> s;
        while(n){
            char op;
            cin >> op;
            if(op == 'P'){
                int data;
                cin >> data;
                s.push(data);
            }else if(op =='O'){
                if(!s.empty()){
                    s.pop();
                }
            }else if(op == 'A'){
                if(!s.empty()){
                    cout << s.top() << endl;
                }else{
                    cout << "E" << endl;
                }
            }
            n--;
        }
        cout << endl;
    }
    return 0;
}