UVa - 12504 Updating a Dictionary

题意

更新字典
记录下第二个字典比第一个字典多的、少的、对应值不相等的

思路

map< string,string>存键值
用set< string> jia,jian,cheng;分别存下三种更新的键
注意特判空字典的情况 .

Both dictionaries could be empty.

AC代码

#include <iostream>
#include <algorithm>
#include <map>
#include <set>

using namespace std;

map<string,string> a,b;
set<string> jia,jian,cheng;

void insert_map( map<string,string> &a, string s )
{
    int i = 1;
    while( s[i] != '\0' )
    {
        int mrk = i;
        while( s[i] != ':' )
            i++;
        string s1(s,mrk,i-mrk);
        mrk = i+1;
        while( s[i] != ',' && s[i] != '}' )
            i++;
        string s2(s,mrk,i-mrk);
        i++;
        a.insert(make_pair(s1,s2));
    }
}

int main()
{
    int T;
    string s1, s2;
    cin >> T;
    while(T--){
        s1 = "";
        s2 = "";
        cin >> s1;
        cin >> s2;
        if( s1 != "{}" )  insert_map(a,s1);
        if( s2 != "{}" )  insert_map(b,s2);
        map<string,string>::iterator it = a.begin();
        for( ; it != a.end(); it++ ){
            if( !b.count(it->first) )
                jian.insert(it->first);
            else
                if( b[it->first] != a[it->first] )
                    cheng.insert(it->first);
        }
        it = b.begin();
        for( ; it != b.end(); it++ )
            if( !a.count(it->first) )
                jia.insert(it->first);
        set<string>::iterator iter;
        if( jia.empty() && jian.empty() && cheng.empty() )
            cout << "No changes" << endl;
        if(!jia.empty()){
            cout << '+' ;
            iter = jia.begin();
            for( ; iter != jia.end(); iter++ ){
                if( iter != jia.begin() )
                    cout << ',';
                cout << *iter ;
            }
            cout << endl;
            jia.clear();
        }
        if(!jian.empty()){
            cout << '-' ;
            iter = jian.begin();
            for( ; iter != jian.end(); iter++ ){
                if( iter != jian.begin() )
                    cout << ',';
                cout << *iter ;
            }
            cout << endl;
            jian.clear();
        }
        if(!cheng.empty()){
            cout << '*' ;
            iter = cheng.begin();
            for( ; iter != cheng.end(); iter++ ){
                if( iter != cheng.begin() )
                    cout << ',';
                cout << *iter ;
            }
            cout << endl;
            cheng.clear();
        }
        cout << endl;
        if(!a.empty())  a.clear();
        if(!b.empty())  b.clear();
    }
    return 0;
}