No.001 Two Sum

Two Sum

• Total Accepted: 262258
• Total Submissions: 1048169
• Difficulty: Easy

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

暴力解法，没有优化思路。

 public class Num1 {
     public int[] twoSum(int[] nums, int target) {
         int [] res = new int [2] ;
         for(int i = 0 ; i < nums.length ; i++){
             if(nums[i] > target){
                 continue ;
             }else{
                 res[0] = i ;
             }
             for(int j = i+1 ; j < nums.length ; j++){
                 if((nums[i]+nums[j]) == target){
                     res[1] = j ;
                     return res ;
                 }else{
                     continue ;
                 }
             }
         }

         return res ;
     }
 }