双指针法

if __name__=="__main__":
    n,m,k = [int(x) for x in input().split()]
    a=[int(x) for x in input().split()]
    b=[int(x) for x in input().split()]

    i=0
    j=m-1

    while a[i]+b[j]!=k and i<n and j>=0:
        if a[i]+b[j]>k:
            j-=1
        elif a[i]+b[j]<k:
            i+=1
        else:
            break
    print(str(i)+" "+str(j))

二分法

def binary_search(nums,target):

    l=0
    r=len(nums)-1

    while l<r:
        mid = (l+r)>>1

        if check(nums[mid],target):
            r=mid
        else:
            l=mid+1

    if target==nums[l]:
        return l

    else:
        return -1

def check(num,target):

    if num>=target:
        return True

    else:
        return False

if __name__=="__main__":
    n,m,x = [int(x) for x in input().split()]

    a=[int(x) for x in input().split()]
    b=[int(x) for x in input().split()]

    for i in range(0,n):
        target = x - a[i]

        index=binary_search(b,target)

        if index > -1:
            print(str(i) + " "+str(index))