两数之和 Leetcode Java

package com.plat.acoal.leetcode;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Stream;

public class TwoNumberSum {
    static class Solution{
          public int[] twoSum(int[] nums,int target){
              for(int i=0;i<nums.length;i++){
                  for(int j=1;j<nums.length;j++){
                      if(nums[j]==target-nums[i]){
                          return new int[]{i,j};
                      }
                  }
              }
             throw  new IllegalArgumentException("no such solution");
          }
    }

    static  class Solution2{
        public int[] twoSum(int[] nums,int target){
            Map<Integer,Integer> map=new HashMap<Integer,Integer>();
            for(int i=0;i<nums.length;i++){
                map.put(nums[i],i);
            }
            for(int i=0;i<nums.length;i++){
                int complement=target-nums[i];
                if(map.containsKey(complement)&&map.get(complement)!=i){
                    return new int[]{nums[i],complement};
                }
            }
            throw new IllegalArgumentException("NO Such sum");
        }
    }

       static class  Solution3{
        public static int[] twoSum(int[] nums,int target){
            Map<Integer,Integer> map=new HashMap<Integer, Integer>();
            for(int i=0;i<nums.length;i++){
                int complement=target-nums[i];
                if(map.containsKey(complement)){
                    return new int[]{map.get(complement),i};
                }
                map.put(nums[i],i);
            }

            throw new IllegalArgumentException("no two num");
        }
       }




    public static void main(String[] args) {
        Solution3 solution3=new Solution3();
        int[] a=solution3.twoSum(new int[]{1, 2, 4},3);

        System.out.println(Arrays.toString(a));
    }
}