Uva 524 相邻素数全排列

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int maxn = 50;
int n;
int isp[maxn];
int vis[maxn];
int A[maxn] = {1};
void pre() {
    memset(vis,0,sizeof(0));
    for(int i = 0; i <= maxn; i++) {
        isp[i] = 1;
    }
    for(int i = 2; i <= maxn; i++) {
        for(int j = i+i; j <= maxn; j+=i) {
            isp[j] = 0;
        }

    }
    isp[0] = 0;
    isp[1] = 0;
}
//bool IsPrime( int num )
//{
//     int tmp = sqrt( num);
//     for(int i= 2;i <=tmp; i++)
//        if(num %i== 0)
//          return 0 ;
//     return 1 ;
//}
void dfs(int cur) {
    if(cur == n && isp[A[0]+A[n-1]]) {
        for(int i = 0; i < n; i++) {
            i ? printf(" %d", A[i]) : printf("%d", A[i]);
        }
        printf("\n");
    }
    //A[cur-1]相邻的上一个数，逆时针
    //A[cur]为当前数
    //枚举每一个没访问过的数
    else for(int i = 2; i <= n; i++) {
        if(!vis[i] && isp[i+A[cur-1]]) {
            A[cur] = i;
            vis[i] = 1;
            dfs(cur+1);
            vis[i] = 0;
        }
    }
}
int main()
{
//    freopen("in.txt","r",stdin);
//    freopen("out.txt","w",stdout);
    int casen = 0;


    while(~scanf("%d",&n)) {
        if(casen!=0) printf("\n");
        pre();
        printf("Case %d:\n",++casen);
        dfs(1);
//        printf("\n");
    }
    return 0;
}

#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
#define MAXN 50
using namespace std;

int n, A[MAXN] = {1}, ispe[MAXN], vis[MAXN];

void dfs(int cur) {
    if(cur == n&& ispe[A[0] + A[n - 1]]) {
        for(int i = 0; i < n; i++) {
            i ? printf(" %d", A[i]) : printf("%d", A[i]);
        }
        printf("\n");
    } else for(int i = 2; i <= n; i++) {

        if(!vis[i]&& ispe[i + A[cur - 1]]) {
            A[cur] = i;
            vis[i] = 1;
            dfs(cur + 1);
            vis[i] = 0;
        }
    }
}

int main() {
//    freopen("in.txt","r",stdin);
//    freopen("out.txt","w",stdout);
    for(int i = 2; i <= 50; i++)
        ispe[i] = 1;
    for(int i = 2; i <= 50; i++)
        for(int j = i + i; j + i <= 50; j += i)
            ispe[j] = 0;
    int kase = 0;
    while(cin >> n) {
        if(kase++)
            printf("\n");
        printf("Case %d:\n", kase);
        dfs(1);
    }
    return 0;
}

#include <iostream>
#include <bits/stdc++.h>
using namespace std;
char str1[90000][50];
char str2[90000][50];

int main()
{
    freopen("in.txt","r",stdin);
    for(int i=0;i<85065;i++)
        gets(str1[i]);
    for(int i=0;i<85065;i++)
        gets(str2[i]);
    for(int i=0;i<85065;i++)
    {
        if(strcmp(str1[i],str2[i])!=0)
            printf("%d\n",i+1);
    }
    return 0;
}