leetcode/code/lc1.java at master · mJackie/leetcode · GitHub

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package code;

* 1. Two Sum

* 题意：返回数组中和为给定数的下标

* 难度：Easy

* 分类：Array, HashTable

* 算法：题目说明了数组中一定有解，且解唯一，所以用哈希表记录已遍历的元素即可

import java.util.HashMap;

import java.util.Map;

public class lc1 {

public static void main(String[] args) {

int[] nums = {2, 7, 11, 15};

int target = 9;

int[] r = twoSum(nums,target);

System.out.println(r[0]);

System.out.println(r[1]);

}

public static int[] twoSum(int[] nums, int target) {

Map<Integer,Integer> map = new HashMap<Integer, Integer>();

int[] result = new int[2];

for (int i = 0; i <nums.length ; i++) {

if(map.containsKey(nums[i])){

result[0] = map.get(nums[i]);

result[1] = i;

return result;

}

map.put(target-nums[i],i);

}

return result;

}

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