力扣90. 子集 II

1、C

/**
 * Return an array of arrays of size *returnSize.
 * The sizes of the arrays are returned as *returnColumnSizes array.
 * Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
 */
void backtracking(int *nums,int numsSize,int start,int *returnSize,int **returnColumnSizes,int *path,int *pathSize,int *visited,int **result){
    result[*returnSize] = (int*)malloc(sizeof(int)*numsSize);
    memcpy(result[*returnSize],path,sizeof(int)*numsSize);
    (*returnColumnSizes)[*returnSize] = *pathSize;
    (*returnSize)++;
    for(int i=start;i<numsSize;i++){
        if(i>0&&nums[i-1]==nums[i]&&visited[i-1]==0){
            continue;
        }
        path[*pathSize] = nums[i];
        visited[i] = 1; 
        (*pathSize)++;
        backtracking(nums,numsSize,i+1,returnSize,returnColumnSizes,path,pathSize,visited,result);
        (*pathSize)--;
        visited[i] = 0; 
    }
}
void QuickSort1(int* a, int left, int right)
{
    if (left >= right)
    {
        return;
    }
    int begin = left, end = right;
    int pivot = begin;
    int key = a[begin];
    while (begin < end)
    {
        //右边找小的，如果不是小于key,继续
        while (begin < end && a[end] >= key)
        {
            end--;
        }
        //找到比key小的，把它放在坑里，换新坑
        a[pivot] = a[end];
        pivot = end;
        //左边找大的，如果不是大于key,继续
        while (begin < end && a[begin] <= key)
        {
            begin++;
        }
        //找到比key大的，把它放在坑里，换新坑
        a[pivot] = a[begin];
        pivot = begin;
    }
    
    a[pivot] = key;//bengin 与 end 相遇，相遇的位置一定是一个坑
    QuickSort1(a, left, pivot - 1);
    QuickSort1(a, pivot + 1, right);
}

int** subsetsWithDup(int* nums, int numsSize, int* returnSize, int** returnColumnSizes){

    QuickSort1(nums,0,numsSize-1);
    *returnSize = 0;
    int *path = (int *)malloc(sizeof(int)*numsSize);
    int **result = (int**)malloc(sizeof(int*)*10001);
    *returnColumnSizes = (int*)malloc(sizeof(int)*10001);
    int *pathSize = (int*)calloc(1,sizeof(int));
    int *visited = (int*)calloc(numsSize,sizeof(int));
    backtracking(nums,numsSize,0,returnSize,returnColumnSizes,path,pathSize,visited,result);
    return result;
}

2、C++

class Solution {
public:
    vector<int> path;
    vector<vector<int>> result;
    void backtracking(vector<int>& nums,int start,vector<bool> &visited){
        result.push_back(path);
        for(int i=start;i<nums.size();i++){
            if(i>0&&nums[i-1]==nums[i]&&visited[i-1]==false){
                continue;
            }
                path.push_back(nums[i]);
                visited[i] = true;
                backtracking(nums,i+1,visited);
                path.pop_back();
                visited[i] = false;
        }
    }
    vector<vector<int>> subsetsWithDup(vector<int>& nums) {
        vector<bool> visited = {false};
        sort(nums.begin(),nums.end());
        backtracking(nums,0,visited);
        return result;
    }
};

3、JAVA

class Solution { 
    LinkedList<Integer> path = new LinkedList<Integer>();
    List<List<Integer>> result = new ArrayList<>();

    void backtracking(int[] nums,int start,boolean[] visited){
        result.add(new ArrayList<>(path));
        for(int i=start;i<nums.length;i++){
            if(i>0 && nums[i-1]==nums[i] && visited[i-1] == false){
                continue;
            }
            path.addLast(nums[i]);
            visited[i] = true;
            backtracking(nums,i+1,visited);
            path.removeLast();
            visited[i] = false;
        }
        return;
    }

    public List<List<Integer>> subsetsWithDup(int[] nums) {
        boolean[] visited = new boolean[nums.length];
        Arrays.sort(nums);
        Arrays.fill(visited,false);
        backtracking(nums,0,visited);
        return result;
    }
}

4、Python

class Solution(object):
    def __init__(self):
        self.path = []
        self.result = []

    def backtracing(self,nums,start,visited):
        self.result.append(self.path[:])
        for i in range(start,len(nums)):
            if i>0 and nums[i-1]==nums[i] and visited[i-1]==False:
                continue
            self.path.append(nums[i])
            visited[i] = True
            self.backtracing(nums,i+1,visited)
            self.path.remove(nums[i])
            visited[i] = False;

    def subsetsWithDup(self, nums):
        """
        :type nums: List[int]
        :rtype: List[List[int]]
        """
        visited = [False]*len(nums)
        nums.sort()
        self.backtracing(nums,0,visited)
        return self.result