大佬们帮忙看看，为什么1，3，4会wa

#include <bits/stdc++.h>
using namespace std;

int main()
{
    int a[130] = {0};
    for (int i = 0; i < 4; i++)
    {
        char tmp[100];
        fgets(tmp,101,stdin);
        int len = strlen(tmp);
        for (int j = 0; j < len; j++)
            a[(int)tmp[j]]++;
    }
    string b;
    int flag = 0;
    int max = -1;
    for (int i = 65; i <= 90; i++)
    {
        if (a[i])
        {
            if (flag)
                b = b + ' ';
            b = b + (char)i;
            flag = 1;
        }
        if (max < a[i])
            max = a[i];
    }
    for (int j = max; j > 0; j--)
    {
        flag = 0;
        for (int i = 65; i <= 90; i++)
        {

            if (a[i])
            {
                if (flag)
                    cout << " ";
                if (a[i] >= j)
                    cout << "*";
                else
                    cout << " ";
                flag = 1;
            }
        }
        cout << endl;
    }
    cout << b;
}