uva 524 Prime Ring Problem-优快云博客

本文链接：https://blog.youkuaiyun.com/lovejava123qqq/article/details/47066931

本文提供了解决UVA 524问题的代码实现，重点在于理解输出格式和使用递归函数DFS进行搜索。代码包括了主要的数据结构和算法逻辑，适用于需要解决类似环形质数排列问题的读者。

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此题比较坑原因是题目没说明输出格式

//
//  main.cpp
//  uva  524 - Prime Ring Problem
//
//  Created by XD on 15/7/26.
//  Copyright (c) 2015年 XD. All rights reserved.
#include <iostream>
#include <string>
#include <queue>
#include <stack>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include<vector>
#include <string.h>
#include <string>
#include <algorithm>
#include <set>
#include <map>
#include <cstdio>
using namespace std ;
using namespace std ;


int prime[21][15] =
{
    {0} ,
    {7,2,4,6,10,12,16,18,21},
    
    {7,1,3,5,9,11,15,17,21},
    
    {6,2,4,8,10,14,16,21},
    
    {6,1,3,7,9,13,15,19,21},
    
    {5,2,6,8,12,14,18,21},
    
    {5,1,5,7,11,13,17,21},
    
    {4,4,6,10,12,16,21},
    
    {4,3,5,9,11,15,21},
    
    {4,2,4,8,10,14,21},
    
    {4,1,3,7,9,13,19,21},
    
    {3,2,6,8,12,18,21},
    
    {3,1,5,7,11,17,19,21},
    
    {2,4,6,10,16,18,21},
    
    {2,3,5,9,15,17,21},
    
    {2,2,4,8,14,16,21},
    
    {2,1,3,7,13,15,21},
    
    {1,2,6,12,14,21},
    
    {1,1,5,11,13,19,21},
    
    {0,4,10,12,18,21},
    {0,3,7,9,11,21}
} ;

int visit[21] ;
int circle[21] ;
int  n ;
void dfs(int i) ;



int main() {
    int i = 1;
    int flag = 0 ;
    while (scanf("%d" ,&n) == 1) {
        circle[1] = 1 ;
        memset(visit, 0, sizeof(visit)) ;
        visit[1] = 1 ;
        if (flag) {
            printf("\n") ;
        }
        flag = 1 ;
        printf("Case %d:\n" ,i) ;
        if (n > 1) {
            dfs(1) ;
        }
        else
        {
            printf("1\n") ;
        }
        i++ ;
        
        
    }
    return 0;
}


void dfs(int i)
{
    int j ;
    if (i == n ) {
        if (1 + circle[n] == 3 || 1 + circle[n] == 5 || 1 + circle[n] == 7 || 1 + circle[n] == 11 || 1 + circle[n] == 13 || 1 + circle[n] == 17 || 1 + circle[n] == 19||1 + circle[n] == 23||1 + circle[n] == 31||1 + circle[n] == 29||1 + circle[n] == 37)
        {
            for ( j = 1; j < n ; j++) {
                printf("%d ",circle[j]) ;
            }
            printf("%d\n" ,circle[j]) ;
        }
        return ;
    }
    int t = prime[circle[i]][1] ;
    for (j = 1; t <= n ; j++) {
        if (visit[prime[circle[i]][j]] == 0) {
            circle[i+1] = t ;
            visit[t] = 1 ;
            dfs(i+1) ;
            visit[t] = 0 ;
        }
        t = prime[circle[i]][j+1] ;
    }
}