PAT甲级A1071---map的常见用法

1071 Speech Patterns (25分)

分析：

先用transform(str.begin(), str.end(), str.begin(), ::tolower);转为小写，然后遍历截取字符串，统计每个单词出现的次数存在map中。最后遍历map找到出现次数最多的单词。

C++：

#include <iostream>
#include <string>
#include <map>
#include <algorithm>

using namespace std;

bool check(char c) {
    if (c >= '0' && c <= '9')return true;
    if (c >= 'a' && c <= 'z')return true;
    return false;
}

int main() {
    string str;
    getline(cin, str);
    transform(str.begin(), str.end(), str.begin(), ::tolower);
    map<string, int> mp;
    int pos = 0;
    while (pos < str.length()) {
        string word;
        while (pos < str.length() && check(str[pos]) == true) {
            word += str[pos];
            pos++;
        }
        if (word != "") {
            if (mp.count(word) == 0) {
                mp[word] = 1;
            } else {
                mp[word]++;
            }
        }
        while (pos < str.length() && check(str[pos]) == false) {
            pos++;
        }
    }
    string res;
    int max = -1;
    for (map<string, int>::iterator iter = mp.begin(); iter != mp.end(); iter++) {
        if (iter->second > max) {
            max = iter->second;
            res = iter->first;
        }
    }
    cout << res << " " << max << endl;
    return 0;
}