给一个整数数组，找到两个数使得他们的和等于一个给定的数 target。
你需要实现的函数twoSum需要返回这两个数的下标, 并且第一个下标小于第二个下标。注意这里下标的范围是 0 到 n-1。样例
给出 numbers = [2, 7, 11, 15], target = 9, 返回 [0, 1].
这道题也是很简单：遍历一下就好
Java版
public class Solution {
/*
* @param numbers: An array of Integer
* @param target: target = numbers[index1] + numbers[index2]
* @return: [index1 + 1, index2 + 1] (index1 < index2)
*/
public int[] twoSum(int[] numbers, int target) {
// write your code here
int length = numbers.length;
int[] t = new int[2];
for(int i = 0 ; i < length ; i++){
for(int j = i+1 ; j<length ; j++){
if(numbers[i] + numbers[j] == target){
t[0] = i;
t[1] = j;
return t;
}
}
}
return null;
}
}
两层for循环感觉不大舒服，所以把其中一层搞掉换成if
改进的Python代码：
class Solution:
"""
@param: numbers: An array of Integer
@param: target: target = numbers[index1] + numbers[index2]
@return: [index1 + 1, index2 + 1] (index1 < index2)
"""
def twoSum(self, numbers, target):
result = []
i = 0
j = 1
while i < len(numbers) and j != i:
if target == (numbers[i]+numbers[j]):
result.append(i)
result.append(j)
break
elif j == len(numbers)-1:
i = i + 1
j = i + 1
else:
j = j+1
return result
加油！！！