2025年Python – 两数之和

编程汇总 • 2025-06-28 20:46 • 阅读 83

给定列表a和一个目标值target，求列表中两数之和为target的值的索引；

a = [1,5,6,8,9,4,5,6,3,2,1,7,5,6,9,8,4,5,6,2,1,0,1,2,0,1,2,5,9,10]
b = [11,55,88,99,66,4,77,33,22,1,6,12,35]

----

穷举（适应性强）

def x(nums,target):

    result = []

    for i in range(len(nums)):

        for j in range(i+1,len(nums)):

            if nums[i]+nums[j] == target:

                result.append((i+1,j+1))

    return result

#print(x(b,10))

双指针（仅限于非重复有序列表的查询）

def y(nums,target):

    result = []

    start = 0

    end = len(nums)-1

    while start < end:

        if nums[start] + nums[end] == target:

            result.append((start+1,end+1))

            end -= 1

            start += 1

        elif nums[start] + nums[end] > target:

            end -= 1

        elif nums[start] + nums[end] < target:

            start += 1

    return result

# print(y(sorted(b),10))

哈希字典查找（仅限于非重复列表的查询）

def z(nums,target):

    result = []

    dict_y = {}

    for i in range(len(nums)):

        m = nums[i]

        if target-m in dict_y:

            result.append((dict_y[target-m]+1,i+1))

        dict_y[m] = i

    return result

#print(z(b,10))

使用字典进行存储（仅限于非重复列表的查询）

def h(nums,target):

    result = []

    xxx = []

    for i in range(len(nums)):

        if target-nums[i] in result:

            xxx.append([result.index(target-nums[i])+1,i+1])

        else:

            result.append(nums[i])

    return xxx

            

print(h(b,10))

2025年Python – 两数之和

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