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leetcode-001.two sum

admin 11月 13, 2020 0

题目描述：

Given an array of integers, return indices of the two numbers such that they add up to a specific target.

You may assume that each input would have exactly one solution, and you may not use the same element twice.

Examples：

1
2
3

Given nums = [2, 7, 11, 15], target = 9,
Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].

思路：

题目比较容易，而且题目说了每组输入必有一解，扫描数组,找到i+j=target即可。

C语言解法：

/**
 * Note: The returned array must be malloced, assume caller calls free().
 */
int* twoSum(int* nums, int numsSize, int target) {
    int* indices;
    int i, j;
    indices = (int*)malloc(2*sizeof(int));
    for(i=0; i<numsSize-1; i++){
        for(j=i+1; j<numsSize; j++){
            if(nums[i]+nums[j] == target){
                indices[0]=i;
                indices[1]=j;
            }
        }
    }
    return indices;
}

C++解法：

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        vector<int> index(2);
        for(int i=0; i<nums.size()-1; i++){
            for(int j=i+1; j<nums.size(); j++){
                if(nums[i]+nums[j] == target){
                    index[0]=i;
                    index[1]=j;
                }
            }
        }
        return index;
    }
};