PAT（乙级）1042.统计字符（20）

This is a simple TEST.  There ARE numbers and other symbols 1&2&3...........

#include <vector>
#include <algorithm>
#include <string>
#include <iostream>
using namespace std;
const int max_n = 130;
int arr[max_n];

struct node{
    char c;
    int cnt;

    node(char c, int cnt){
        this->c = c;
        this->cnt = cnt;
    }
};

vector<node> vec;

bool cmp(node a, node b){
    if(a.cnt!=b.cnt)
        return a.cnt > b.cnt;
    else
        return a.c < b.c;
}

void transform(string& s){
    for(int i=0; i<s.length(); ++i){
        if(s[i]>='A' && s[i]<='Z')
            s[i] += 32;
    }
}

int main(){
    //freopen("in.txt", "r", stdin);
    fill(arr, arr+max_n, 0);
    string s;
    getline(cin, s);
    transform(s);
    for(int i=0; i<s.length(); ++i){
        if( (s[i]>='a'&&s[i]<='z')){
            arr[(int)s[i]] ++;
        }
    }

    for(int i=0; i<max_n; ++i){
        if(arr[i]!=0){
            vec.push_back(node(i, arr[i]));
        }
    }
    sort(vec.begin(), vec.end(), cmp);
    printf("%c %d\n", vec[0].c, vec[0].cnt);
    return 0;
}