演算法:兩數之和
Problem Description
兩數之和
給定一個整數陣列 nums 和一個目標值 target,請你在該陣列中找出和為目標值的那兩個 整數,並返回他們的陣列下標。
你可以假設每種輸入只會對應一個答案。但是,你不能重複利用這個陣列中同樣的元素。
示例:
給定 nums = [2, 7, 11, 15], target = 9 因為 nums[0] + nums[1] = 2 + 7 = 9 所以返回 [0, 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].
Solution Code
public class Solution { 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 match"); } }
Reference
https://leetcode-cn.com/problems/two-sum
https://leetcode.com/problems/two-sum/