HDU 5025 Saving Tang Monk

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优先队列或普通队列的特殊处理。

法一：

//First Edit Time:	2014-09-20 22:37
//Last Edit Time:	2014-09-20 22:40
#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <map>
#include <set>
#include <cmath>
using namespace std;
#define MAXN 110
int vis[MAXN][MAXN][1<<6][15];
char map1[MAXN][MAXN];
struct point{
    int x,y,step,stats,statk;
    bool operator<(point y)const {
        return step>y.step;
    }
}st,et;
struct snack{
    int x,y;
}S[10];
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
int n,m,scnt,k;
int bfs(){
    queue <point> q;
    point now,next;
    q.push(st);
    memset(vis,0,sizeof(vis));
    vis[st.x][st.y][st.stats][st.statk]=1;
    while(!q.empty()){
        now=q.front();
        q.pop();
        if(now.x==et.x&&now.y==et.y&&now.statk==k){
            return now.step;
        }
        if(map1[now.x][now.y]=='S'){
            int flag=0;
                for(int i=1;i<=scnt;i++){
                    if(now.x==S[i].x&&now.y==S[i].y){
                        flag=i;
                        break;
                    }
                }
                if((now.stats>>(flag-1))&1);
                else {
                    now.stats|=(1<<(flag-1));
                    now.step++;
                    q.push(now);
                    continue;
                }
        }
        for(int i=0;i<4;i++){
            next.x=now.x+dx[i];
            next.y=now.y+dy[i];
            next.step=now.step+1;
            next.statk=now.statk;
            next.stats=now.stats;
            if(next.x<1||next.x>n||next.y<1||next.y>n)continue;
            if(map1[next.x][next.y]=='#')continue;
            if(map1[next.x][next.y]-'0'==now.statk+1){
                next.statk=now.statk+1;
            }
            if(vis[next.x][next.y][next.stats][next.statk])continue;
            vis[next.x][next.y][next.stats][next.statk]=1;
            q.push(next);
        }
    }
    return -1;
}
int main()
{
    while(~scanf("%d%d",&n,&m)&&(n||m)){
        k=m;
        m=n;
        scnt=0;
        int flag1=0,flag2=0;
        for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++){
            scanf(" %c",&map1[i][j]);
            if(map1[i][j]=='S'){
                scnt++;
                S[scnt].x=i;
                S[scnt].y=j;
            }
            if(map1[i][j]=='K'){
                st.x=i;st.y=j;
                st.step=0;st.stats=0;st.statk=0;
                flag1=1;
            }
            if(map1[i][j]=='T'){
                et.x=i;et.y=j;
                flag2=1;
            }
        }
        if(!flag1||!flag2){
            puts("impossible");
            continue;
        }
        int ff=bfs();
        if(ff==-1)puts("impossible");
        else printf("%d\n",ff);
    }
    return 0;
}

法二：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <map>
#include <set>
#include <cmath>
using namespace std;
#define MAXN 110
int vis[MAXN][MAXN][1<<6][15];
char map1[MAXN][MAXN];
struct point{
    int x,y,step,stats,statk;
    bool operator<(point y)const {
        return step>y.step;
    }
}st,et;
struct snack{
    int x,y;
}S[10];
int dx[]={0,0,1,-1};
int dy[]={1,-1,0,0};
int n,m,scnt,k;
int bfs(){
    priority_queue <point> q;
    point now,next;
    q.push(st);
    memset(vis,0,sizeof(vis));
    vis[st.x][st.y][st.stats][st.statk]=1;
    while(!q.empty()){
        now=q.top();
        q.pop();
        if(now.x==et.x&&now.y==et.y&&now.statk==k){
            return now.step;
        }
        for(int i=0;i<4;i++){
            next.x=now.x+dx[i];
            next.y=now.y+dy[i];
            next.step=now.step+1;
            next.statk=now.statk;
            next.stats=now.stats;
            if(next.x<1||next.x>n||next.y<1||next.y>n)continue;
            if(map1[next.x][next.y]=='#')continue;
            if(map1[next.x][next.y]=='S'){
                int flag=0;
                for(int i=1;i<=scnt;i++){
                    if(next.x==S[i].x&&next.y==S[i].y){
                        flag=i;
                        break;
                    }
                }
                if((next.stats>>(flag-1))&1);
                else {
                    next.stats|=(1<<(flag-1));
                    next.step++;
                }
            }
            if(map1[next.x][next.y]-'0'==now.statk+1){
                next.statk=now.statk+1;
            }
            if(vis[next.x][next.y][next.stats][next.statk])continue;
            vis[next.x][next.y][next.stats][next.statk]=1;
            q.push(next);
        }
    }
    return -1;
}
int main()
{
    while(~scanf("%d%d",&n,&m)&&(n||m)){
        k=m;
        m=n;
        scnt=0;
        int flag1=0,flag2=0;
        for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++){
            scanf(" %c",&map1[i][j]);
            if(map1[i][j]=='S'){
                scnt++;
                S[scnt].x=i;
                S[scnt].y=j;
            }
            if(map1[i][j]=='K'){
                st.x=i;st.y=j;
                st.step=0;st.stats=0;st.statk=0;
                flag1=1;
            }
            if(map1[i][j]=='T'){
                et.x=i;et.y=j;
                flag2=1;
            }
        }
        if(!flag1||!flag2){
            puts("impossible");
            continue;
        }
        int ff=bfs();
        if(ff==-1)puts("impossible");
        else printf("%d\n",ff);
    }
    return 0;
}