练习---two sum

package solution;

/**
 * https://oj.leetcode.com/problems/two-sum/
 *  Given an array of integers, find two numbers such that they add
 *         up to a specific target number. The function twoSum should return
 *         indices of the two numbers such that they add up to the target, where
 *         index1 must be less than index2. Please note that your returned
 *         answers (both index1 and index2) are not zero-based. You may assume
 *         that each input would have exactly one solution. Input: numbers={2,
 *         7, 11, 15}, target=9 Output: index1=1, index2=2
 */
public class Two_Sum {

    public static void main(String[] args) {
        int[] numbers = { 2, 7, 11, 15 };
        int target = 9;
        // Output: index1=1, index2=2
        work(numbers, target);
    }

    /**

     * 假设numbers不空 假设numbers.length>1 假设numbers里面没有负数 假设target大于0 假设numers是递增有序的

     *
     * @param numbers
     * @param target
     * @return
     */
    private static int[] work(int[] numbers, int target) {
        int[] result = new int[2];
        for (int p = 0; p < numbers.length - 1; p++) {
            for (int q = p + 1; q < numbers.length; q++) {
                if (numbers[p] + numbers[q] == target) {
                    result[0] = p + 1;
                    result[1] = q + 1;
                    System.out.println(result[0] + " " + result[1]);
                }
            }
        }
        return result;
    }

}