本问题对应的 leetcode 原文链接:剑指 Offer 57. 和为s的两个数字

问题描述

输入一个递增排序的数组和一个数字s,在数组中查找两个数,使得它们的和正好是s。如果有多对数字的和等于s,则输出任意一对即可。

示例 1:

输入:nums = [2,7,11,15], target = 9
输出:[2,7] 或者 [7,2]

示例 2:

输入:nums = [10,26,30,31,47,60], target = 40
输出:[10,30] 或者 [30,10]

限制:

  • 1 <= nums.length <= 10^5
  • 1 <= nums[i] <= 10^6

解题思路

视频讲解直达: 本题视频讲解

代码实现

class Solution {
    public int[] twoSum(int[] nums, int target) {
        if(nums == null || nums.length < 2){
            return new int[0];
        }

        int i = 0, j = nums.length - 1;

        while(i < j){
            if(nums[i] + nums[j] > target){
                j--;
            }else if(nums[i] + nums[j] < target){
                i++;
            }else{
                return new int[]{nums[i], nums[j]};
            }
        }

        return new int[0];
    }
}

Python

class Solution(object):
    def twoSum(self, nums, target):
        """
        :type nums: List[int]
        :type target: int
        :rtype: List[int]
        """
        if nums is None or len(nums) < 2:
            return []

        i, j = 0, len(nums) - 1

        while i < j:
            if nums[i] + nums[j] > target:
                j -= 1
            elif nums[i] + nums[j] < target:
                i += 1
            else:
                return [nums[i], nums[j]]

        return []

C++

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        if (nums.empty() || nums.size() < 2) {
            return {};
        }

        int i = 0, j = nums.size() - 1;

        while (i < j) {
            if (nums[i] + nums[j] > target) {
                j--;
            } else if (nums[i] + nums[j] < target) {
                i++;
            } else {
                return {nums[i], nums[j]};
            }
        }

        return {};
    }
};

Go

func twoSum(nums []int, target int) []int {
    if nums == nil || len(nums) < 2 {
        return []int{}
    }

    i, j := 0, len(nums) - 1

    for i < j {
        if nums[i] + nums[j] > target {
            j--
        } else if nums[i] + nums[j] < target {
            i++
        } else {
            return []int{nums[i], nums[j]}
        }
    }

    return []int{}
}

JS

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    if (nums == null || nums.length < 2) {
        return [];
    }

    let i = 0,
        j = nums.length - 1;

    while (i < j) {
        if (nums[i] + nums[j] > target) {
            j--;
        } else if (nums[i] + nums[j] < target) {
            i++;
        } else {
            return [nums[i], nums[j]];
        }
    }

    return [];
};

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