UVa 12504 Updating a Dictioinary

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题目：UVa 12504 Updating a Dictionary

分析：

键值对可用map来处理，即map[ key ] = value。

因为有三种情况要讨论，股分别用set保存对应变化的键值，顺便排序。

读入需要注意，通过冒号来区分key和value，不同键值对用 ',' 和 '}‘区分，而 '}' 代表此行的读入停止。

代码：

#include <iostream>#include <map>#include <set>#include <string>#include <vector>#include <cctype>#include <sstream>using namespace std;map<string, string> key;map<string, int> vis;set<string> add, rem, cha;void disp(set<string> x) {    int len = x.size(), i = 0;    for (set<string>::iterator it = x.begin(); it != x.end(); it++, i++) {        cout << *it;        if (i < len - 1)            cout << ',';    }    cout << '\n';}int main() {    int t;    cin >> t;    while (t--) {        key.clear();        vis.clear();        add.clear();        rem.clear();        cha.clear();        char c;        int flag = 0;        string a, b, s;        cin >> s;        stringstream ss(s);        while (ss >> c) {            // cout << "c:" << c << '\n';            if (!flag) {                if (isalpha(c))                    a.push_back(c);                else if (c == ':')                    flag = !flag;            }            else {                if (isalnum(c))                    b.push_back(c);                else {                    flag = !flag;                    key[a] = b;                    vis[a] = 0;                    // cout << "a:" << a << ", b:" << b << '\n';                    a.clear();                    b.clear();                    if (c == '}')                        break;                }            }        }/*        for (map<string,string>::iterator ip = key.begin(); ip != key.end(); ip++)            cout << ip->first << ":" << ip->second << "\n";*/        flag = 0;        int count = 0;        cin >> s;        stringstream sss(s);        while (sss >> c) {            // cout << "c:" << c << '\n';            if (!flag) {                if (isalpha(c))                    a.push_back(c);                else if (c == ':')                    flag = 1;            }            else {                if (isalnum(c))                    b.push_back(c);                else {                    flag = 0;                    // cout << "a:" << a << ", b:" << b << "\n";                    if (!key.count(a))                        add.insert(a);                    else if (key[a] == b)                        vis[a] = 1;                    else {                        cha.insert(a);                        vis[a] = 1;                    }                    a.clear();                    b.clear();                    if (c == '}')                        break;                }            }        }        for (map<string, int>::iterator it = vis.begin(); it != vis.end(); it++)            if (it->second == 0)                rem.insert(it->first);        if (add.empty() && rem.empty() && cha.empty()) {            cout << "No changes\n\n";            continue;        }        if (!add.empty()) {            cout << '+';            disp(add);        }        if (!rem.empty()) {            cout << '-';            disp(rem);        }        if (!cha.empty()) {            cout << '*';            disp(cha);        }        cout << '\n';    }    return 0;}

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