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.
Example:
Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].
UPDATE (2016/2/13):
The return format had been changed to zero-based indices. Please read the above updated description carefully.
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public class Solution {
public int[] twoSum(int[] numbers, int target) {
if(numbers.length <= 1){
return new int[]{};
}
int ans[] = new int[2];
HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
for(int idx = 0; idx < numbers.length; idx++){
map.put(numbers[idx], idx);
}
for(int idx = 0; idx < numbers.length; idx++){
if(map.containsKey(target - numbers[idx]) && map.get(target - numbers[idx]) != idx ){
ans[0] = Math.min(map.get(target - numbers[idx]), idx);
ans[1] = Math.max(map.get(target - numbers[idx]), idx);
break;
}
}
return ans;
}
}
