Children of the Candy Corn(BFS+DFS POJ3083)

~题目链接~

http://poj.org/problem?id=3083

Sample Input

2
8 8
########
#......#
#.####.#
#.####.#
#.####.#
#.####.#
#...#..#
#S#E####
9 5
#########
#.#.#.#.#
S.......E
#.#.#.#.#
#########

Sample Output

37 5 5
17 17 9

DFS  进行左转和右转的数目统计

BFS  进行最短路的查找

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<queue>
#define maxn 50

using namespace std;

int map[maxn][maxn],sp[maxn][maxn],n,m;
int f[4][2]= {{-1,0},{0,-1},{1,0},{0,1}};

struct node
{
    int x,y;
} S,E;

queue<node>Q;

int DFS(int x1,int y1,int x2,int y2,int sn,int step)
{
    if(x1==x2 && y1==y2)
        return step;
    sn=(sn+1)%4;
    while(!map[x1+f[sn][0]][y1+f[sn][1]])
        sn=(sn+3)%4;
    step++;
    return DFS(x1+f[sn][0],y1+f[sn][1],x2,y2,sn,step);
}

int BFS(struct node S,struct node E)
{
    while(!Q.empty())
        Q.pop();
    Q.push(S);
    sp[S.x][S.y]=1;
    while(!Q.empty())
    {
        struct node V;
        S=Q.front();
        for(int i=0; i<4; i++)
        {
            V.x=S.x+f[i][0];
            V.y=S.y+f[i][1];
            if(V.x<0 || V.x>=m || V.y<0 || V.y>=n)
                continue;
            if(!sp[V.x][V.y] && map[V.x][V.y])
            {
                sp[V.x][V.y]=sp[S.x][S.y]+1;
                Q.push(V);
            }
            if(V.x==E.x && V.y==E.y && map[V.x][V.y])
                return sp[V.x][V.y];
        }
        Q.pop();
    }
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int i,j;
        char c;
        scanf("%d%d",&n,&m);
        memset(map,0,sizeof(map));
        memset(sp,0,sizeof(sp));
        getchar();
        for(i=0; i<m; i++)
        {
            for(j=0; j<n; j++)
            {
                scanf("%c",&c);
                if(c=='.' || c=='S' || c=='E')
                    map[i][j]=1;
                if(c=='S')
                {
                    S.x=i;
                    S.y=j;
                }
                if(c=='E')
                {
                    E.x=i;
                    E.y=j;
                }
            }
            getchar();
        }
        int l=DFS(S.x,S.y,E.x,E.y,1,1);//左转 从入到出深度优先遍历
        int r=DFS(E.x,E.y,S.x,S.y,1,1);//右转 从出到入深度优先遍历
        int k=BFS(S,E);//最短路 广度优先遍历
        printf("%d %d %d
",l,r,k);
    }

    return 0;
}