题目

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代码部分一（26ms 55.61%）

class Solution {
    public String[] findRestaurant(String[] list1, String[] list2) {
        int len1 = list1.length;
        int len2 = list2.length;
        if(len1 == 0 || len2 == 0) return new String[]{};           // 数组为空直接返回空数组
        
        int minimum = Integer.MAX_VALUE;
        List<String> list = new ArrayList<>();
        Map<String, Integer> map = new HashMap<>();
        Map<String, Integer> map1 = new HashMap<>();
        
        for(int i = 0; i < len1; i++){                              //将其中一个数组存入HashMap
            map1.put(list1[i], i);
        }
        for(int i = 0; i < len2; i++){                              //寻找与其他数组相同的字符串，并记录下标和 and 最小小标和
            if(map1.containsKey(list2[i])){
                int sum = i + map1.get(list2[i]);
                map.put(list2[i], sum);
                minimum = minimum > sum ? sum : minimum;
            }
        }
        for(String s : map.keySet()){
            if(map.get(s) == minimum)
                list.add(s);
        }
        
        String[] res = new String[list.size()];                     // 结果转换为String[]
        for(int i = 0; i < res.length; i++){
            res[i] = list.get(i);
        }
        return res;
        
    }
}

 

代码部分二（26ms 56.68%）

class Solution {
    public String[] findRestaurant(String[] list1, String[] list2) {
        List<String> res = new LinkedList<String>();
        Map<String, Integer> indexMap = new HashMap<String, Integer>();
        
        for(int i = 0; i < list1.length; i++){
            indexMap.put(list1[i], i);
        }
        Integer sum = list1.length + list2.length - 2;
        for(int i = 0; i < list2.length; i++){
            Integer temp = indexMap.put(list2[i], 1);               //若已存在 key-value 返回之前的value ,否则返回 null
            if(temp != null){
                if((i + temp) == sum){
                    res.add(list2[i]);
                    continue;
                }
                if((i + temp) < sum){
                    sum = i + temp;
                    res.clear();
                    res.add(list2[i]);
                    
                }
            }
        }
        
        return res.toArray(new String[res.size()]);
    }
}

 

代码部分三（21ms 89.21%）

class Solution {
    public String[] findRestaurant(String[] list1, String[] list2) {
        Map<String, Integer> map = new HashMap<>();
        List<String> list = new ArrayList<>();
        int min = Integer.MAX_VALUE;
        for (int i = 0; i < list1.length; i++)
            map.put(list1[i],i);
        for (int i = 0; i < list2.length; i++) {
            Integer j = map.get(list2[i]);
            if (j != null && i + j <= min) {
                if (i + j < min) {
                    list.clear();
                    min = i + j;
                }
                list.add(list2[i]);
            }
        }
        return list.toArray(new String[0]);
    }
}