Question:
Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.
Note: The solution set must not contain duplicate triplets.
For example, given array S = [-1, 0, 1, 2, -1, -4],
A solution set is: [ [-1, 0, 1], [-1, -1, 2] ]
Solution:
class Solution { public: vector<vector<int>> res; void find(vector<int>& v , int s, int e , int data){ while(s < e){ int sum = v[s] + v[e] ; if(sum == -data){ vector<int> tmp; tmp.push_back(v[s]); tmp.push_back(v[e]); tmp.push_back(data); res.push_back(tmp); while(s != e && v[s] == v[s+1]){s++;} while(e != 0 && v[e] == v[e-1]){e--;} s++; e--; } else if(sum < -data ){ s++; } else{ e--; } } } vector<vector<int>> threeSum(vector<int>& nums) { sort(nums.begin(),nums.end()); int len = nums.size(); for(int i = 0 ; i < len ; i++){ if(i > 0 && nums[i] == nums[i-1])continue; find(nums,i+1,len-1,nums[i]); } return res; } };新聞熱點
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