【LeetCode刷题】-- 170.两数之和III-数据结构设计

170.两数之和III-数据结构设计

方法：使用哈希表

class TwoSum {Map<Integer,Integer> map;public TwoSum() {map = new HashMap<>();}public void add(int number) {//key存元素，value为出现的次数map.put(number,map.getOrDefault(number,0) + 1);}public boolean find(int value) {//通过Map.entrySet遍历key和valuefor(Map.Entry<Integer,Integer> entry : map.entrySet()){int diff = value - entry.getKey();if(diff != entry.getKey()){if(map.containsKey(diff)){return true;}}//当前元素和差值相等，且当前元素出现次数大于1，返回trueelse{if( map.get(diff) > 1){return true;}}}return false;}
}/*** Your TwoSum object will be instantiated and called as such:* TwoSum obj = new TwoSum();* obj.add(number);* boolean param_2 = obj.find(value);*/