LeetCode三数之和最接近目标-优快云博客

本文介绍了一个LeetCode上的经典问题：寻找数组中三个整数的组合，使其和最接近给定的目标值，并返回这三个整数的和。通过使用Python实现，遍历数组并计算所有可能的三数组合，找到距离目标最近的和。

题目来自leetcode.com

Given an array nums of n integers and an integer target, find three integers in nums such that the sum is closest to target. Return the sum of the three integers. You may assume that each input would have exactly one solution.

class Sol():
    def __init__(self, a1=0,a2=0,a3=0):
        self.a1 = a1
        self.a2 = a2
        self.a3 = a3
    def update(self,a1,a2,a3):
        self.a1 = a1
        self.a2 = a2
        self.a3 = a3

def _num(a1,a2,a3,arr,target):
    sum = arr[a1]+arr[a2]+arr[a3]
    sum -= target
    if sum >=0:
        return sum
    else:
        return -1*sum

ans = Sol()

target = input("input the target num ")
num = input("input the number of array ")
target = int(target)
num = int(num)
arr = []
a = 0
while a < num:
    arr.append(int(input()))
    a += 1

a = 0
cl = 100000
while a < num-2:
	b = a+1
	while b <num-1:
		c = b+1
		while c <num:
			d = _num(a,b,c,arr,target)
			print(d)
			if cl > d:
				cl = d
				ans.update(a,b,c)
				print(ans.a1)
			c += 1
		b += 1
	a += 1
cl = arr[ans.a1]+arr[ans.a2]+arr[ans.a3]
print('the sum that is cloest to the target is '+str(cl)+'.('+str(arr[ans.a1])+'+'+str(arr[ans.a2])+'+'+str(arr[ans.a3])+'='+str(cl)+')')