LeetCode---2.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].

大意为：

输入一组数组与一个目标数，当存在数组中的某2个数的和为目标数时，输出该2个数的索引下标。

解题思路：

在第一层循环上从0开始循环，第二层循环从i+1开始循环，避免遍历过往重复的数据以及自身的和。

附上代码：

public int[] twoSum(int[] nums, int target) {
for (int i = 0; i < nums.length; i++) {
for (int j = i + 1; j < nums.length; j++) {
if (nums[i] + nums[j] == target) {
return new int[]{i, j};
}
}
}
throw new IllegalArgumentException("No solution");
}