LeetCode 491 递增子序列 2023.11.22
class Solution {
public:
vector<int> cur;
set<vector<int>> result;
void backtracking(vector<int> nums, int start)
{
if(cur.size() > 1)
result.insert(cur);
for (int i = start; i < nums.size(); i++)
{
if(cur.empty() || (!cur.empty() && nums[i] >= cur[cur.size()-1]))
{
cur.push_back(nums[i]);
backtracking(nums, i+1);
cur.pop_back();
}
else
continue;
}
}
vector<vector<int>> findSubsequences(vector<int>& nums) {
cur.clear();
result.clear();
if(nums.empty())
return vector<vector<int>>(result.begin(), result.end());
backtracking(nums, 0);
return vector<vector<int>>(result.begin(), result.end());
}
};
LeetCode 46 全排列 2023.11.22
class Solution {
public:
vector<int> cur;
vector<vector<int>> result;
unordered_set<int> set;
void backtracking(vector<int> nums)
{
if(cur.size() == nums.size())
{
result.push_back(cur);
return;
}
for (int i = 0; i < nums.size(); i++)
{
if(set.find(nums[i]) == set.end())
{
cur.push_back(nums[i]);
set.insert(nums[i]);
backtracking(nums);
cur.pop_back();
set.erase(nums[i]);
}
}
}
vector<vector<int>> permute(vector<int>& nums) {
cur.clear();
result.clear();
set.clear();
if(nums.empty())
return result;
backtracking(nums);
return result;
}
};
LeetCode 47 全排列-ii 2023.11.22
- [题目链接]https://leetcode.cn/problems/permutations-ii/)
- 代码随想录讲解[链接]
class Solution {
public:
vector<int> cur;
vector<vector<int>> result;
unordered_map<int, int> map;
void backtracking(vector<int> nums)
{
if(cur.size() == nums.size())
{
result.push_back(cur);
return;
}
for (int i = 0; i < nums.size(); i++)
{
if(map[nums[i]])
{
map[nums[i]]--;
cur.push_back(nums[i]);
backtracking(nums);
map[nums[i]]++;
cur.pop_back();
}
while (i < nums.size()-1 && nums[i] == nums[i+1])
i++;
}
}
vector<vector<int>> permuteUnique(vector<int>& nums) {
cur.clear();
result.clear();
map.clear();
for (int i = 0; i < nums.size(); i++)
map[nums[i]]++;
if(nums.empty())
return result;
sort(nums.begin(), nums.end());
backtracking(nums);
return result;
}
};