# C++ Solution(52ms), How to run fast?

• ``````class Solution {
public:
vector<vector<int>> threeSum(vector<int>& nums) {
vector<vector<int>> result;
if (nums.size()<3) return result;

int target = 0;
int tmpNum = 0;
// index is not need, but sorted is need
std::sort(nums.begin(), nums.end());
int count = nums.size();
vector<int> tmp(5);

for (int i = 0; i<count - 2;) {
// the sum is 0, so the first num must not larger than 0
if (nums[i] > 0) break;
int j = i + 1;
int k = count - 1;
// the sum is 0, so the last num must not smaller than 0
if (nums[k] < 0) break;
while (j<k) {
// the sum is 0, so the last num must not smaller than 0
if (nums[k] < 0) break;
int sum = nums[i] + nums[j] + nums[k];
if (sum == 0)
{
tmp.clear();
tmp.push_back(nums[i]);
tmp.push_back(nums[j]);
tmp.push_back(nums[k]);
result.push_back(tmp);
// change j to nums[j] != nums[old j]
do {
j++;
} while (j<k && nums[j] == nums[j - 1]);
// change k to nums[k] != nums[old k]
do {
k--;
} while (j<k && nums[k] == nums[k + 1]);
}
else if (sum > 0) {
// change k to nums[k] != nums[old k]
do {
k--;
} while (j<k && nums[k] == nums[k + 1]);
}
else {
// change j to nums[j] != nums[old j]
do {
j++;
} while (j<k && nums[j] == nums[j - 1]);
}
}
// change i to nums[i] != nums[old i]
do {
i++;
} while (i<count - 2 && nums[i] == nums[i - 1]);
}
return result;
}
};``````

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