标签:not tar solution 测试用例 用例 bar import length 4sum
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.
Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].
class Solution {
public int[] twoSum(int[] nums, int target) {
int[] indice = new int[2];
if(nums.length==0)
return indice;
for(int i = 0; i<nums.length;i++){
int tmp = target - nums[i];
for(int j = i+1; j<nums.length;j++){
if(tmp == nums[j]){
indice[0]=i;
indice[1]=j;
}
}
}
return indice;
}
}
采用HashMap每次添加值,key为具体值,value 为 indice。
import java.util.*;
class Solution {
public int[] twoSum(int[] nums, int target) {
Map<Integer,Integer> hashTable = new HashMap<>();
int [] indice = new int[2];
if(nums == null)
return indice;
for(int i = 0; i<nums.length;i++){
int tmp = target - nums[i];
if(hashTable.containsKey(tmp)){
indice[0] = i;
indice[1] = hashTable.get(tmp);
break;
}else{
hashTable.put(nums[i],i);
}
}
return indice;
}
}
可以看到时间复杂度提高了40倍。
标签:not tar solution 测试用例 用例 bar import length 4sum
原文地址:https://www.cnblogs.com/clnsx/p/12236574.html