全排列的几种方法

void print(){
    int i;
    for (i = 1; i <= n; i++)
        cout << consist[i] << ' ';
    cout << endl;
}
void dfs(int k){//深搜函数，当前是第k格
    int i;
    if (k == n) {//填满了的时候
        print();//输出当前解
        return;
    }
    for (i = 1; i <= n; i++){//1-n循环填数
        if (!fuck[i]){//如果当前数没有用过
            fuck[i] = 1;//标记一下
            consist[k + 1] = i;//把这个数填入数组
            dfs(k + 1);//填下一个
            fuck[i] = 0;//回溯
        }
    }
}

#include <iostream>
#include <stdio.h>
#include <vector>
using namespace std;

int N;
vector<int> arr;

void dfs(vector<int>ans, int k) {
    if (k == N) {
        for (int i = 0; i < N; i++) {
            cout << ans[i] << ' ';
        }
        cout << endl;
        return;
    }

    for (int i = k; i < N; i++) {
        swap(ans[i], ans[k]);
        dfs(ans, k + 1);
    }
}

int main() {
    cin >> N;
    for (int i = 0; i < N; i++) {
        arr.push_back(i + 1);
    }

    dfs(arr, 0);
    return 0;
}

#include <iostream>
#include <fstream>
using namespace std;

int arr[10];
void process(int k,int n) {
    if (k == n) {
        for (int i = 1; i <= n; i++) {
            cout << arr[i] << ' ';
        }
        cout << endl;
        return;
    }
    for (int i = k; i <= n; i++) {
        swap(arr[i], arr[k]);
        process(k + 1, n);
        swap(arr[i], arr[k]);
    }
}
int main() {
    fstream fin("data.in");
    int n;
    fin >> n;
    for (int i = 1; i <= n; i++) {
        arr[i] = i;
    }
    process(1,n);
}

#include <iostream>
#include <algorithm>
#include <fstream>
using namespace std;
int arr[10];
int main() {
    fstream fin("data.in");
    int n;
    fin >> n;
    for (int i = 1; i <= n; i++) {
        arr[i] = i;
    }
    while (next_permutation(arr + 1, arr + n + 1)) {
        for (int i = 1; i <= n; i++) {
            cout << arr[i] << ' ';
        }
        cout << endl;
    }
}