public class _003TwoSum {

     public static void main(String[] args) {

         int a[]={3,22,4,7,8,22};

         display(twoSum3(a,30));

     }

     　　//暴力搜索法

      public static int[] twoSum(int[] numbers, int target) {

           int index[] = {0,0};

             for(int i=0; i<numbers.length; i ++){

                 for(int j=i+1; j<numbers.length; j++){

                     if(target == numbers[i]+numbers[j]){

                         index[0] = i+1;

                         index[1] = j+1;

                         return index;

                     }

                 }

             }

             return index;  

         }

      //使用map，因为刚好是两个值，一个值一个下表map刚好可以储存然后用map的containsKey的方法

      public static  int[] twoSum2(int[] numbers, int target) {

             int index[] = {0,0};

             HashMap<Integer, Integer> num = new HashMap<Integer,Integer>();

             for(int i=0;i<numbers.length;i++){

                 num.put(numbers[i], i);

             }

             for(int i=0;i<numbers.length;i++){

                 int temp = target-numbers[i];

                 if(num.containsKey(temp)&&i<num.get(temp)){

                     index[0] = i+1;

                     index[1] = num.get(temp)+1;

                     break;

                 }

             }

             return index;

         }

      public static void display(int a[])

      {

          for(int i=0;i<a.length;i++)

              System.out.println(a[i]);

      }

     }