No.1 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。

 1 public class Num1 {
 2     public int[] twoSum(int[] nums, int target) {
 3         int [] res = new int [2] ;
 4         for(int i = 0 ; i < nums.length ; i++){
 5             if(nums[i] > target){
 6                 continue ;
 7             }else{
 8                 res[0] = i ;
 9             }
10             for(int j = i+1 ; j < nums.length ; j++){
11                 if((nums[i]+nums[j]) == target){
12                     res[1] = j ;
13                     return res ;
14                 }else{
15                     continue ;
16                 }
17             }
18         }
19
20         return res ;
21     }
22 }