五百年前

package com.sea.leetcode;

import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
/**
 * Created by Sea on 2016/11/16.
 */
public class TwoSum {
    public int[] twoSum(int[] nums, int target) {
        int numsArrLength = nums.length;
        int[] result = new int[2];
        for (int i = 0; i < numsArrLength - 1; i++) {
            for (int j = i + 1; j < numsArrLength; j++) {
                if (target == nums[i] + nums[j]) {
                    result[0] = i;
                    result[1] = j;
                }
            }

        }
        return result;
    }

    public int[] twoSumByHash(int[] nums, int target) {
        int numsArrLength = nums.length;
        Map<Integer, Integer> numberMap = new HashMap<Integer, Integer>();
        int[] result = new int[2];
        for (int i = 0; i < numsArrLength; i++) {
            if (numberMap.get(nums[i]) == null) {
                numberMap.put(nums[i], i);
            }
            Integer n = numberMap.get(target - nums[i]);
            if (n != null && n != i) {
                result[0] = n;
                result[1] = i;
                return result;
            }

        }

        return result;
    }

    public static void main(String[] args) {
        int[] nums = {3, 2,7,4};
        int target = 6;
        TwoSum ts = new TwoSum();
        System.out.println("********TWOFOR************");
        System.out.println(new Date().getTime());
        int[] result = ts.twoSum(nums, target);
        System.out.println(new Date().getTime());
        System.out.println("********HASH************");
        System.out.println(new Date().getTime());
        int[] result1 = ts.twoSumByHash(nums, target);
        System.out.println(new Date().getTime());
        System.out.println(Arrays.toString(result1));
    }
}