[BFS] 机器人搬重物 洛谷

本文章仅纪念自己 把200多行代码压到80多行
https://www.luogu.org/problemnew/show/P1126
vj上也有 csu1975 说真的 直接输出12 在csu上就过了 洛谷数据多点
23333 太可怕了 一年后看到给改了改
改版后

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 50+5;
const int cx[]= {0,0,1,-1};
const int cy[]= {1,-1,0,0};
const int xx[]= {-1,0,-1,0};
const int yy[]= {-1,-1,0,0};
const int walkx[]= {1,0,-1,0};
const int walky[]= {0,-1,0,1};
const char tof[]="SWNE";
int n,m,x,pos,sx,sy,ex,ey,flag;
int mp[maxn][maxn];
bool vis[maxn][maxn][26];

bool check(int x,int y,char s) {
	if(x==1||y==1) return 1;
	if(x<1||y<1||x>n||y>m) return 1;
	if(vis[x][y][s-'A']) return 1;
	for(int i=0; i<4; i++)
		if(mp[x+xx[i]][y+yy[i]]==1) return 1;
	return 0;
}

int repos(char s) {
	for(int i=0; i<4; i++) if(tof[i]==s) return i;
}

struct node {
	int sp;
	char ms;
	int x,y;
} st,tp,tmp;

void bfs() {
	queue<node> que;
	que.push(st);
	vis[st.x][st.y][st.ms-'A']=1;
	while(!que.empty()) {
		tmp=que.front();
		que.pop();
		if(tmp.x==ex&&tmp.y==ey) {
			printf("%d\n",tmp.sp);
			return ;
		}
		for(int i=0; i<4; i++) {
			pos=repos(tmp.ms);
			tp.ms=tmp.ms;
			if(i==0) {
				tp.ms=tof[(pos+1)%4];
				if(!check(tmp.x,tmp.y,tp.ms)) {
					vis[tmp.x][tmp.y][tp.ms-'A']=1;
					que.push(node {tmp.sp+1,tp.ms,tmp.x,tmp.y});
				}
				tp.ms=tof[(pos+3)%4];
				if(!check(tmp.x,tmp.y,tp.ms)) {
					vis[tmp.x][tmp.y][tp.ms-'A']=1;
					que.push(node {tmp.sp+1,tp.ms,tmp.x,tmp.y});
				}
			} else  {
				tp.x=tmp.x+walkx[pos]*(4-i);
				tp.y=tmp.y+walky[pos]*(4-i);
				flag=1;
				for(int j=3-i; j>=0; j--)
					if(check(tp.x+(-1)*j*walkx[pos],tp.y+(-1)*j*walky[pos],tp.ms)) flag=0;
				if(flag) vis[tp.x][tp.y][tp.ms-'A']=1,que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
			}
		}
	}
	printf("-1\n");
	return ;
}

int main() {
	scanf("%d %d",&n,&m);
	for(int i=1; i<=n; i++) for(int j=1; j<=m; j++)
			scanf("%d",&mp[i][j]);
	scanf("%d %d %d %d %c",&sx,&sy,&ex,&ey,&st.ms);
	st=node {0,st.ms,sx+1,sy+1};
	ex++,ey++,n++,m++;
	bfs();
	return 0;
}

改版前

#include <iostream>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <cstring>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <list>
using namespace std;
typedef long long ll;
const int maxn = 50+5;
const int cx[]= {0,0,1,-1};
const int cy[]= {1,-1,0,0};

const int xx[]={-1,0,-1,0};
const int yy[]={-1,-1,0,0};

int n,m,x;
int mp[maxn][maxn];
bool vis[maxn][maxn][26];
int sx,sy,ex,ey;

bool check(int x,int y,char s) {
    if(x==1||y==1) return 1;
    if(x<1||y<1||x>n||y>m) return 1;
    if(vis[x][y][s-'A']) return 1;
    for(int i=0; i<4; i++) {
        if(mp[x+xx[i]][y+yy[i]]==-1) return 1;
    }
    return 0;
}

struct node {
    int sp;
    char ms;
    int x,y;
} st,tp,tmp;

void bfs() {
    queue<node> que;
    que.push(st);
    vis[st.x][st.y][st.ms-'A']=1;
    while(!que.empty()) {
        tmp=que.front();
        que.pop();
    // cout<<tmp.x<<" "<<tmp.y<<" "<<tmp.ms<<" "<<tmp.sp<<endl;
        if(tmp.x==ex&&tmp.y==ey) {
            printf("%d\n",tmp.sp);
            return ;
        }
        int nx,ny;
        for(int i=0; i<5; i++) {
            if(i==0) {
                if(tmp.ms=='S') tp.ms='W';
                if(tmp.ms=='W') tp.ms='N';
                if(tmp.ms=='N') tp.ms='E';
                if(tmp.ms=='E') tp.ms='S';
                if(check(tmp.x,tmp.y,tp.ms)) continue;
                vis[tmp.x][tmp.y][tp.ms-'A']=1;
                que.push(node {tmp.sp+1,tp.ms,tmp.x,tmp.y});
            }
            if(i==1) {
                if(tmp.ms=='S') tp.ms='E';
                if(tmp.ms=='W') tp.ms='S';
                if(tmp.ms=='N') tp.ms='W';
                if(tmp.ms=='E') tp.ms='N';
                if(check(tmp.x,tmp.y,tp.ms)) continue;
                vis[tmp.x][tmp.y][tp.ms-'A']=1;
                que.push(node {tmp.sp+1,tp.ms,tmp.x,tmp.y});
            }
            if(i==4) {
                if(tmp.ms=='N') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x-1;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='S') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x+1;				
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='W') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y-1;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='E') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y+1;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
            }
            if(i==3) {
                if(tmp.ms=='N') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x-2;
                    if(check(tp.x+1,tp.y,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='S') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x+2;
                    if(check(tp.x-1,tp.y,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='W') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y-2;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y+1,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='E') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y+2;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y-1,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
            }
            if(i==2) {
                if(tmp.ms=='N') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x-3;
                    if(check(tp.x+2,tp.y,tp.ms)) continue;
                    if(check(tp.x+1,tp.y,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='S') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y;
                    tp.x=tmp.x+3;
                    if(check(tp.x-2,tp.y,tp.ms)) continue;
                    if(check(tp.x-1,tp.y,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='W') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y-3;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y+2,tp.ms)) continue;
                    if(check(tp.x,tp.y+1,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
                if(tmp.ms=='E') {
                    tp.ms=tmp.ms;
                    tp.y=tmp.y+3;
                    tp.x=tmp.x;
                    if(check(tp.x,tp.y-2,tp.ms)) continue;
                    if(check(tp.x,tp.y-1,tp.ms)) continue;
                    if(check(tp.x,tp.y,tp.ms)) continue;
                    vis[tp.x][tp.y][tp.ms-'A']=1;
                    que.push(node {tmp.sp+1,tp.ms,tp.x,tp.y});
                }
            }
        }
    }
    printf("-1\n");
    return ;
}

int main() {
    scanf("%d %d",&n,&m);
    memset(mp,-1,sizeof(mp));
    for(int i=1; i<=n; i++) {
        for(int j=1; j<=m; j++) {
            scanf("%d",&x);
            if(x==1) continue;
            else mp[i][j]=x;
        }
    }
    n++,m++;
    scanf("%d %d %d %d %c",&sx,&sy,&ex,&ey,&st.ms);
    st=node{0,st.ms,sx+1,sy+1};
    ex++,ey++;
    bfs();
    return 0;
}