Leetcode the Sum

1. Topics

Given an array of integers, find the numbers such that they add up to a specific target number.

The function twosum should return indices of the numbers such that they add up to the target, where index1 must is Les S than Index2. Please note that your returned answers (both Index1 and INDEX2) is not zero-based.

You may assume this each input would has exactly one solution.

Input: numbers={2, 7, one, target=9
Output: index1=1, index2=2

2. One solution

typedef struct NODE{INT Originalindex;int Val;node () {};node (int index, int v): Originalindex (Index), Val (v) {}} Node;bool Compare (const node& A, const node& b) {return a.val < B.val;} Class Solution {public:        vector<int> twosum (vector<int> &numbers, int target) {       Vector<int  > Result;int length = numbers.size ();vector<node> nums (length); for (int i = 0; i < numbers.size (); ++i) {nums[i] = Node (i, numbers[i]);} Sort (Nums.begin (), nums.end (), compare), int left = 0;int right = Length-1;while (left < right) {int sum = Nums[left].va L + nums[right].val;if (sum = = target) {result.push_back (min (nums[left].originalindex + 1, Nums[right].originalindex + 1) ); Result.push_back (max (Nums[left].originalindex + 1, Nums[right].originalindex + 1); break;} else if (sum < target) {left++;} else{right--;}} return result;}    ;

Idea: First sort, then add and end to judge, if too small, the left Mark Index to the right to move one, if too big, the right mark Index to the left to move until found.

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Leetcode the Sum