2016北京赛区网赛C（模拟）

最新推荐文章于 2018-10-24 16:13:07 发布

Emma1997

最新推荐文章于 2018-10-24 16:13:07 发布

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分类专栏： acm水题

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本文介绍了一种通过字符串处理和模拟的方式统计文本中特定短语出现频率的算法。该算法利用了C++标准库中的字符串操作及Map容器来实现短语的识别与计数，并找出出现次数最多的短语。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

思考：
1、别忘了清空数组等
2、想好了再写

代码写得比较冗余。其实主要代码段就是

int l = strlen (s);
        for (int i = 0; i <= l; i++) {
            if (s[i] == ',' || s[i] == '.' || s[i] == '\0') {
                if (flag1 == 2) {
                    string s2 = first;
                    s2 += ' ';
                    s2 += second;
                    //cout << first << " " << second << " " << s2 << endl;
                    //cout << flag1 << " " << flag2 << endl;
                    if (mp.count (s2)) {
                        mp[s2]++;
                    } else {
                        mp[s2] = 1;
                    }
                    first.clear();
                    second.clear();
                    maxnum = max (maxnum, mp[s2]);
                }
                first.clear();
                flag1 = 1;
                flag2 = 1;
            } else if (s[i] == ' ') {
                if (flag2) continue;
                if (i != 0 && s[i - 1] == ' ') continue;
                if (flag1 == 1) {
                    flag1 = 2;
                } else if (flag1 == 2) {
                    string s2 = first;
                    s2 += ' ';
                    s2 += second;
                    //cout << s2 << endl;
                    //cout << flag1 << " " << flag2 << endl;
                    if (mp.count (s2)) {
                        mp[s2]++;
                    } else {
                        mp[s2] = 1;
                    }
                    first = second;
                    second.clear();
                    maxnum = max (maxnum, mp[s2]);
                }

            } else {
                flag2 = 0;
                if (flag1 == 1) first += s[i];
                if (flag1 == 2) second += s[i];
            }
        }

用Map存储所有的短语出现过的次数，最后扫一遍找出现最多次的短语就好了。
上面的哪一段代码实现的功能是把所有的短语都加入到map里。这道题是纯模拟，比较麻烦，不过处理好了短语之后，也就好做多了。

#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <queue>

using namespace std;
const int maxn = 600;
map<string, int> mp;

int main()
{
    #ifndef ONLINE_JUDGE
    freopen ("in.txt", "r", stdin);
    #endif // ONLINE_JUDGE
    char s[maxn];
    while (gets (s)) {
        int maxnum = 0;
        mp.clear();
        int flag1 = 1;
        int flag2 = 1;
        string first, second;
        first.clear();
        second.clear();
        int l = strlen (s);
        for (int i = 0; i <= l; i++) {
            if (s[i] == ',' || s[i] == '.' || s[i] == '\0') {
                if (flag1 == 2) {
                    string s2 = first;
                    s2 += ' ';
                    s2 += second;
                    //cout << first << " " << second << " " << s2 << endl;
                    //cout << flag1 << " " << flag2 << endl;
                    if (mp.count (s2)) {
                        mp[s2]++;
                    } else {
                        mp[s2] = 1;
                    }
                    first.clear();
                    second.clear();
                    maxnum = max (maxnum, mp[s2]);
                }
                first.clear();
                flag1 = 1;
                flag2 = 1;
            } else if (s[i] == ' ') {
                if (flag2) continue;
                if (i != 0 && s[i - 1] == ' ') continue;
                if (flag1 == 1) {
                    flag1 = 2;
                } else if (flag1 == 2) {
                    string s2 = first;
                    s2 += ' ';
                    s2 += second;
                    //cout << s2 << endl;
                    //cout << flag1 << " " << flag2 << endl;
                    if (mp.count (s2)) {
                        mp[s2]++;
                    } else {
                        mp[s2] = 1;
                    }
                    first = second;
                    second.clear();
                    maxnum = max (maxnum, mp[s2]);
                }

            } else {
                flag2 = 0;
                if (flag1 == 1) first += s[i];
                if (flag1 == 2) second += s[i];
            }
        }
        while (gets (s)) {
            if (s[0] == '#') break;
            int flag1 = 1;
            int flag2 = 1;
            string first, second;
            int l = strlen (s);
            for (int i = 0; i <= l; i++) {
                if (s[i] == ',' || s[i] == '.' || s[i] == '\0') {
                    if (flag1 == 2) {
                        string s2 = first;
                        s2 += ' ';
                        s2 += second;
                        //cout << s2 << endl;
                        //cout << flag1 << " " << flag2 << endl;
                        if (mp.count (s2)) {
                            mp[s2]++;
                        } else {
                            mp[s2] = 1;
                        }
                        first.clear();
                        second.clear();
                        maxnum = max (maxnum, mp[s2]);
                    }
                    first.clear();
                    flag1 = 1;
                    flag2 = 1;
                } else if (s[i] == ' ') {
                    if (flag2) continue;
                    if (i != 0 && s[i - 1] == ' ') continue;
                    if (flag1 == 1) {
                        flag1 = 2;
                    } else if (flag1 == 2) {
                        string s2 = first;
                        s2 += ' ';
                        s2 += second;
                       // cout << s2 << endl;
                       // cout << flag1 << " " << flag2 << endl;
                        if (mp.count (s2)) {
                            mp[s2]++;
                        } else {
                            mp[s2] = 1;
                        }
                        first = second;
                        second.clear();
                        maxnum = max (maxnum, mp[s2]);
                    }
                    flag2 = 1;
                } else {
                    flag2 = 0;
                    if (flag1 == 1) first += s[i];
                    if (flag1 == 2) second += s[i];
                }
            }
        }
        map<string, int>::iterator it;
        for (it = mp.begin(); it != mp.end(); it++) {
            if (it->second == maxnum) {
                cout << it->first << ":" << maxnum << endl;
                break;
            }
        }
    }
    return 0;
}