Description
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].
public class Solution {
public int[] twoSum(int[] nums, int target) {
}
}
Solution
import java.util.HashMap;
import java.util.Map;
/**
* 1. Two Sum
*
* @author kimtaeng
* created on 2018. 1. 9
*/
public class Solution {
public int[] twoSum(int[] nums, int target) {
Map<Integer, Integer> map = new HashMap<Integer, Integer>();
for (int i = 0; i < nums.length; i++) {
int otherValue = target - nums[i];
if (map.containsKey(otherValue)) {
return new int[] { map.get(otherValue), i };
}
map.put(nums[i], i);
}
throw new IllegalArgumentException("No two sum solution");
}
}
