LeetCode 1 - Two Sum ( JAVA )

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].

public class Solution {
    public int[] twoSum(int[] nums, int target) {
        int [] a = new int[2];
        for(int i=0;i<nums.length;i++){
            for(int j=0;j<nums.length;j++){
                if(i!=j&&target==nums[i]+nums[j]){
                    a[0]=i;
                    a[1]=j;
                    break;
                }
            }
        }
        return a;
    }
}

总结：题目比较简单，使用两个循环嵌套即可，空间复杂度O（N2），代码效率不高。