[LeetCode] Permutations

最新推荐文章于 2025-09-10 22:03:14 发布

原创最新推荐文章于 2025-09-10 22:03:14 发布 · 352 阅读

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文章标签：

#leetcode #recursion #backtracking

Recursion with backtracking.

class Solution {
public:
    void helper(vector<vector<int> > &result, vector<int> &num, vector<int> cur, vector<bool> used, int n) {
        if(n==num.size()) {
            result.push_back(cur);
            return;
        }
        for(int i=0;i<num.size();i++) {
            if(!used[i]) {
                cur[n]=num[i];
                used[i]=true;
                helper(result, num, cur, used,n+1);
                used[i]=false;
            }
        }
    }
    vector<vector<int> > permute(vector<int> &num) {
        vector<int> cur;
        vector<bool> used;
        for(int i=0;i<num.size();i++) {
            cur.push_back(0);
            used.push_back(false);
        }
        vector<vector<int> > r;
        helper(r, num, cur, used, 0);
        return r;
    }
};