poj 3126

来源：互联网发布：淘宝打折软件叫什么编辑：程序博客网时间：2024/05/01 23:45

看上去像是一道质数题，实际上就是BFS。。比较水，不多说直接上代码。

#include <stdio.h>#include <queue>#include <string.h>#define INF 10000000using namespace std;int judge[10005],dp[10005];void solution(){    int i,j;    judge[0]=1;    judge[1]=1;    for(i=2;i<=10000;i++){        if(judge[i]==0)        for(j=i+i;j<=10000;j+=i){            judge[j]=1;        }    }    return;}int po(int n){    int e=1;    if(n==0)        return 1;    for(int i=0;i<n;i++)        e*=10;    return e;}int main(){    int n,m,i,j,t;    int p,date,charge;    memset(judge,0,sizeof(judge));    solution();    //memset(dp,0,sizeof(dp));    scanf("%d",&t);    while(t--){        scanf("%d%d",&n,&m);        queue<int> q;        for(i=1000;i<=10000;i++) dp[i]=INF;        dp[n]=0;        q.push(n);        while(q.size()){            p=q.front(); q.pop();            charge=p;            if(p==m) break;            for(i=1;i<=4;i++){                date=charge%10;                charge=charge/10;                for(j=0;j<10;j++){                    int nx=(p-date*po(i-1))+po(i-1)*j;                    //printf("nx=%d\n",nx);                    if(nx>=1000&&nx<=9999&&judge[nx]==0/*&&nx!=n*/&&dp[nx]==INF){                            q.push(nx);                        dp[nx]=dp[p]+1;                    }                }            }        }        //if(dp[m]<INF)        printf("%d\n",dp[m]);        //else        //printf("no\n");    }    return 0;}

0 0