1. Two Sum

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, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,Because nums[0] + nums[1] = 2 + 7 = 9,return [0, 1].

題意:給定一個數組還有一個目標數，輸出數組中兩個數加起來等於目標數的所有組合(但不能兩個相同的元素進行相加)

題解:對這個數組進行兩次歷遍，若加起來等於目標數，則加入答案中，若元素相同則跳過

package LeetCode.Easy;public class TwoSums {public int[] twoSum(int[] nums, int target) {        for(int i = 0; i < nums.length; i++ ) {                        for(int j = 0; j < nums.length; j ++) {                                if(i == j)                    continue;                                    if(nums[i] + nums[j] == target) {                    int [] ans =  new int[2];                    ans[0] = i;                    ans[1] = j;                    return ans;                }            }        }                    return null;    }}