Question
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].
answer
/**
* 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].
* Created by pafer on 17-5-5.
*/
public class Solution {
public static int[]
twoSum(
int[] nums,
int target) {
Map<Integer, Integer> numMap =
new HashMap<Integer, Integer>();
for (
int i =
0; i < nums.length; i++) {
Integer tmpIndex = numMap.get(target - nums[i]);
if (tmpIndex !=
null) {
return new int[]{tmpIndex, i};
}
numMap.put(nums[i], i);
}
return null;
}
public static void main(String[] args) {
int [] nums = {
2,
7,
11,
15};
int[] ints = twoSum(nums,
17);
if (ints !=
null) {
System.out.println(ints[
0] +
" / " + ints[
1]);
}
}
}
href
https://leetcode.com/articles/two-sum/
