java - 比较 hashMap 值

Question

我正在练习一些面试题，但不知道如何比较 hashMap 值。前提是你有一本带弦的杂志。您必须从杂志中剪下适当数量的字符以形成勒索字条。我已经设法将字符和字符的出现次数添加到 hashMap，但我如何比较这两个 hashMap 以确定我有足够的字母。任何指导将不胜感激。

杂志 = {g=2, =14, d=2, e=2, a=4, n=1, o=5, l=4, m=1, .=1, k=1, I =2, h=2, i=6, w=1, T=1, u=1, t=2, s=3, r=1, y=2}赎金 = {w=1, =3, o=1, l=4, k=1, I=1, y=1, i=2}

String mag = "this is what I said Im going to do. i really like you a lot";
        String ransom = "i will kill you";

        Map<Character,Integer> map = new HashMap<Character,Integer>();
        Map<Character,Integer> ransomMap = new HashMap<Character,Integer>();

        for(int i = 0; i < mag.length() -1; i++)
        {
            char c = mag.charAt(i);
            if(!map.containsKey(c))
            map.put(c, 1);
            else{
                int value = map.get(c);
                map.put(c,++value);
            }
        }

        System.out.println(map);

        for(int i = 0; i < ransom.length()-1; i++ )
        {
        char c = ransom.charAt(i);
        if(!ransomMap.containsKey(c))
            ransomMap.put(c,1);
        else
        {
            int value = (ransomMap.get(c));
            ransomMap.put(c,++value);
        }
        }
        System.out.println(ransomMap);
    }

Answer 1

检查赎金记录中的每个字母，看看报纸上是否有足够的字母:

boolean enoughLetters(Map<Character, Integer> magMap, Map<Character,Integer> ransomMap) {
    for( Entry<Character, Integer> e : ransomMap.entrySet() ) {
        Character letter = e.getKey();
        Integer available = magMap.get(letter);
        if (available == null || e.getValue() > available) return false;
    }
    return true;
}