12 条题解

  • 1
    @ 2024-4-12 12:23:47 
    using namespace std;
int main(){
	int n;
	cin>>n;
	int a[1010];
	for(int i=1; i<=n; i++){
		a[i]=i;
	}
	do{
		for(int i=1; i<n; i++){
			printf("%d ",a[i]);
		}
		printf("%d\n",a[n]);
	}while(next_permutation(a+1,a+n+1));//直接用内置的全排列函数写就行了，注意先输出已有的第一中排列，所以要用do-while
	return 0;
}
    • 0
      @ 2025-4-5 21:56:55 
      #include<bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> v;
    for(int i=1;i<=n;i++){
        v.push_back(i);
    }
    do{
        for(int num :v){
            cout << num << " ";
        }
        cout << endl;
    }while(next_permutation(v.begin(),v.end()));
}
      • 0
        @ 2025-3-15 13:20:06 
        /*
#include <iostream>
#include <vector>
using namespace std;

// 递归函数，用于生成全排列
void permute(vector<int>& nums, size_t start, vector<vector<int>>& result) {
    if (start == nums.size() - 1) { //递归终止条件
        result.push_back(nums);  // 将当前排列加入结果
    } else {
        for (size_t i = start; i < nums.size(); i++) { //从start位置开始遍历
            //核心代码 ===》靠近终止条件 ==》 start+1 代表上一个位置被固定 
            //那start == nums.size() - 1 代表已经到最终位置了
            swap(nums[start], nums[i]);  // 交换元素使得每一个元素都在start位置试试
            permute(nums, start + 1, result);  // 递归生成排列
            swap(nums[start], nums[i]);  // 恢复原状
        }
    }
}

int main() {
    int n;
    cin >> n;

    vector<int> nums(n);
    for (int i = 0; i < n; i++) {
        nums[i] = i + 1;  // 初始化数组
    }

    vector<vector<int>> result;  // 存储所有排列
    permute(nums, 0, result);  // 生成全排列

    // 输出所有排列
    for (const vector<int>& perm : result) {
        for (int num : perm) {
            cout << num << " ";
        }
        cout << endl;
    }

    for ( size_t i = 0; i < result.size(); i++ ) {
        for ( size_t j = 0; j < result[i].size(); j++ ) {
            cout << result[i][j] << " ";
        }
        if(i != result.size() - 1)
        cout << endl;
    }

    return 0;
}
*/
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> nums(n);
    for (int i = 0; i < n; i++) {
        nums[i] = i + 1;  // 初始化数组
    }

    // 使用 std::next_permutation 生成所有排列
    //next_permutation 的作用是将一个序列（如数组或向量）重新排列，使其成为字典序中的下一个排列。
    //如果当前序列已经是字典序中的最大排列（例如 321），那么它会将序列重置为最小排列（例如 123）。
    do {
        for (int num : nums) {
            cout << num << " ";
        }
        cout << endl;
    } while (next_permutation(nums.begin(), nums.end()));

    return 0;
}
        • 0
          @ 2025-3-11 15:32:12 
          #include <iostream>
#include <algorithm>

using namespace std;

int main() {
    int n;
    cin >> n;

    int a[1000];

    for (int i = 0; i < n; i++) {
        a[i] = i + 1;
    }

    do {
		for (int i = 0; i < n; i++) {
			cout << a[i];
            if (i != n - 1) {
                cout << " ";
            }
		}
		cout << endl;
	} while (next_permutation(a, a + n));

    return 0;
}
          • 0
            @ 2025-1-7 23:58:48 
            // https://dashoj.com/p/82
#include <bits/stdc++.h>

using namespace std;
const int N = 15;
int n, cnt = 0;
bool nb[N];
vector<int> cl;

void out() {
	for (int i = 0; i < cl.size(); i++) {
		cout << cl[i] << ' ';
	}
	cout << endl;
}

void dfs(int x, int c) {
	if (cl.size() == n) {
		out();
		return;
	}
	for (int i = 1; i <= n; i++) {
		if (nb[i]) {
			nb[i] = false;
			cl.push_back(i);
			dfs(i, c + 1);
			cl.pop_back();
			nb[i] = true;
		}

	}
}

int main() {
	fill(&nb[0], &nb[0] + N, true);
	cin >> n;
	for (int i = 1; i <= n; i++) {
		nb[i] = false;
		cl.push_back(i);
		dfs(i, 1);
		cl.pop_back();
		nb[i] = true;
	}
	return 0;
}
            • 0
              @ 2024-4-11 13:45:11

              #include<bits/stdc++.h> using namespace std;

              int num[10],str[10]; int ans=0; void dfs(int n,int n2){

              for(int i=1;i<=n2;i++) { if(str[i]!=0) continue; str[i] =1; num[n]=i; dfs(n+1,n2); str[i]=0; }

              if(n==n2) { for(int i=1;i<=n2;i++) { cout<<num[i]<<' '; } cout<<endl; }

              } int main() { int n2; cin>>n2; dfs(1,n2); return 0; }

              • 0
                @ 2024-4-10 21:13:30 
                #include <bits/stdc++.h>
using namespace std;
int n = 0;
vector<int> v;

int main(){
	cin >> n;
	for(int i = 1 ; i <= n ; i++){
		v.push_back(i);
	}
	
	do{
		for(int i = 0 ; i <n ; i++){
			cout << v[i] << " ";
		}
		cout << endl;	
	}	while(next_permutation(v.begin(), v.end()));
		
	return 0;
}
                • 0
                  @ 2024-4-10 16:12:53 
                  #include<iostream>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<vector>
using namespace std;
const int N=12;
int used[N];
int nums[N];
vector<int> res;
int n;
void dfs(int countNum){
	if(countNum>n){
		for(auto temp:res) cout<<temp<<" ";
		cout<<endl;
		return;
	}
	for(int i=0;i<n;i++){
		if(used[i]) continue;
//		标记为被使用过
		used[i]=1;
		res.push_back(nums[i]);
		dfs(countNum+1);
		used[i]=0;
		res.pop_back();
	}
}
int main(){

	cin>>n;
	for(int i=0;i<n;i++) nums[i]=i+1;
	dfs(1);
	
	return 0;
}
                  • 0
                    @ 2024-4-8 21:00:50

                    提供两种解法：

                    next_permutation

                    #include <bits/stdc++.h>
using namespace std;
const int N = 20;
int a[N];
int n;
int main(){
    scanf("%d",&n);
    for (int i = 1; i <= n; ++i) {
        a[i] = i;
    }
    do{
        for (int i = 1; i <= n; ++i) {
            printf("%d ",a[i]);
        }
        printf("\n");
    }while(next_permutation(a + 1,a + n + 1));
    return 0;
}

                    DFS

                    #include <bits/stdc++.h>
using namespace std;
const int N = 20;
int vis[N];
int a[N];
int n;
void dfs(int x){
    if (x > n) {
        for (int i = 1; i <= n; ++i) {
            printf("%d ",a[i]);
        }
        printf("\n");
    }
    for (int i = 1; i <= n; ++i) {
        if(!vis[i]) {
            vis[i] = 1;
            a[x] = i;
            dfs(x + 1);
            a[x] = 0;
            vis[i] = 0;
        }
    }
}
int main(){
    scanf("%d",&n);
    dfs(1);
    return 0;
}
                    • 0
                      @ 2024-4-7 21:50:43 
                      n = int(input())
nums = [i for i in range(1,n+1)]
res = []
path = []
used = [0]*n
def dfs(nums,path,used,n):
    if len(path) == n:
        print(*path)

    for i in range(n):
        if used[i]:
            continue
        used[i] = 1
        path.append(nums[i])
        dfs(nums,path,used,n)
        path.pop()
        used[i] = 0

dfs(nums,path,used,n)
                      • 0
                        @ 2024-4-6 23:13:11

                        #include <bits/stdc++.h> using namespace std; int a[20], x, n;

                        int b[20];

                        void dfs(int x) { if (x > n) { for (int i = 1; i < n; i++) cout << a[i] << " "; cout << a[n] << endl; return; } for (int i = 1; i <= n ; i++) {

                        	if (b[i] == 0) {
		b[i] = 1;
		a[x] = i;
		dfs(x + 1);
		b[i] = 0;
	}
}

                        }

                        int main() { cin >> n; dfs(1); return 0; }

                        • 0
                          @ 2024-4-5 22:42:38 
                          #include <cstdio>
#include <vector>
#include <functional>

using namespace std;

int main() {
	int n;
	scanf("%d", &n);
	
	vector<char> ita(n + 1, 0);
	vector<int> res;
	function<void()> dfs = [&]() {
		if (res.size() >= n) {
			for (int& it : res)
				printf("%d ", it);
			printf("\n");
			return;
		}
		
		for (int i = 1; i <= n; ++i) {
			if (!ita[i]) { // 是否已经放过
				ita[i] = 1;
				res.push_back(i); // 放
				dfs();
				res.pop_back(); // 不放
				ita[i] = 0;
			}
		}
	};
	
	dfs();
	
	return 0;
}
                          • 1

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                          信息

                          ID
                          82
                          时间
                          2000ms
                          内存
                          512MiB
                          难度
                          5
                          标签
                          递交数
                          728
                          已通过
                          293
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