第一题(两个数之和) class solution (publicintdhytwosum ) intdhynums,int target ) { HashMapInteger,Integer hashMap=new HashMap for(intI=0; i nums.length; I ) { int tmp=target - nums[i]; //if(Hashmap.containskey(tmp ) ) { intdhy result={i,Hashmap.get ) tmp; 返回结果; }Hashmap.put(nums[I],I ); }返回空值; }