LeetCode OJ - Permutations (C++) (try 19 times)

為了練習尋找實習時會碰到的問題，我用別人推薦的 LeetCode online judge。
希望能直接寫程式，不用事先編譯就能直接AC。

To practice future interview question, I use LeetCode online judge.
I am trying to type code directly on website without compile in other tool.

編譯錯誤次數 Compile Error number: 8
嘗試次數 Try number: 19 (AC: 1) (WA: 6)(TLE/TO: 3) (RE: 1) (CE: 8)
是否事先在其他工具編譯 if compile first in other tool: No

使用的程式語言 using programming language: C++
以前是否看過 seen this problem before: No

點這裡看題目 Click here to see this Problem!

Note: use fill(visit.begin(), visit.end(), false);

CE: variables' name typo, miss semi-colon

WA:
1. first I use the "bool* visit;" and "visit = new bool[size];" It passed many cases, but in some case, it will fail...I don't know why. Last, I change it into vector<bool> and use resize() to change its size.

2. Some variable scope mistakes... If you use recursive, you can pass the variable as a parameter or just put it as global variable.

	class Solution {
	private:
	vector<vector<int> > v;
	public:
	vector<vector<int> > permute(vector<int> &num) {
	v.clear();
	int size = num.size();
	vector<int> visit, save;
	visit.resize(size);
	save.resize(size);
	fill(visit.begin(), visit.end(), false);//fill false to vector: visit
	dfs(num, save, visit, 0, size);
	return v;
	}
	void dfs(vector<int> num, vector<int> save, vector<int> visit, int now, int size){
	if(now == size){
	v.push_back(save);//save one possible permutation
	return;
	}
	for(int i = 0; i < size; i++){
	if(!visit[i]){
	visit[i] = true;
	save[now] = num[i];
	//recursive to permute rest number
	dfs(num, save, visit, now + 1, size);
	visit[i] = false;
	}
	}
	}
	};

view raw LeetCode OJ - Permutations (C++).cpp hosted with ❤ by GitHub

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