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原创最新推荐文章于 2026-09-20 14:20:17 发布 760 阅读 AI 写同款· GEO 优化 ›

STM32HAL库基于外部Flash+FatFs模拟U盘方式进行固件拷贝升级(详解) STM32HAL库基于外部Flash+FatFs模拟U盘方式进行固件拷贝升级阅读详情

谁能帮我看看为什么第一份代码是AC，而第二份是WA呢- -！，就改了起火时间bfs那个判断条件而已

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <map>
#include <queue>
#include <ctime>
#include <set>
#include <deque>
#include <string>
#define MP make_pair
#define PB push_back
#define SZ(x) ((int)(x).size())
#define REP(i,n) for (int _n=n,i=0; (i)<_n; ++(i))
#define FOR(i,a,b) for (int _b=b,i=(a);i<=_b;++(i))
#define FOREACH(it,c) for ( __typeof((c).begin()) it=(c).begin(),ite=(c).end(); it!=ite; ++it )
int rint() { int x; if(~scanf("%d",&x)) return x; return -1; }
typedef long long LL;
const int inf=~0U>>1;
using namespace std;

const int maxN=1010;
int t,n,m,dx[]={-1,1,0,0},dy[]={0,0,-1,1},sx,sy,ft[maxN][maxN];
char s[maxN][maxN];
bool vis[maxN][maxN];
struct Node{
	int time,x,y;
	Node(){}
	Node(int _time,int _x,int _y):time(_time),x(_x),y(_y){}
}no;
queue<Node> q;

int main(){
	t=rint();
	while(t--){
		n=rint(),m=rint();
		REP(i,n) scanf("%s",s[i]);
		REP(i,n) REP(j,m) {
			ft[i][j]=inf;
			if(s[i][j]=='F') ft[i][j]=0,q.push(Node(0,i,j));
			else if(s[i][j]=='J') sx=i,sy=j;
		}
		while(!q.empty()){
			no=q.front();
			q.pop();
			REP(i,4){
				int nx=no.x+dx[i],ny=no.y+dy[i];
				if(nx<0||nx>=n||ny<0||ny>=m||s[nx][ny]=='#'||ft[nx][ny]<=no.time+1) continue;
				ft[nx][ny]=no.time+1;
				q.push(Node(ft[nx][ny],nx,ny));
			}
		}/*
		REP(i,n){
			REP(j,m) cout<<ft[i][j]<<" ";
			puts("");
		}*/
		memset(vis,false,sizeof(vis));
		int ans=-1;
		q.push(Node(0,sx,sy));
		vis[sx][sy]=true;
		while(!q.empty()){
			no=q.front();
			q.pop();
			if(ans!=-1) continue;
			REP(i,4){
				int nx=no.x+dx[i],ny=no.y+dy[i];
				if(nx<0||nx>=n||ny<0||ny>=m){
					ans=no.time+1;
					break;
				}
				if(s[nx][ny]=='#'||vis[nx][ny]) continue;
				vis[nx][ny]=true;
				if(ft[nx][ny]<=no.time+1) continue;
				q.push(Node(no.time+1,nx,ny));
			}
		}
		if(ans==-1) puts("IMPOSSIBLE");
		else cout<<ans<<endl;
	}
	return 0;
}

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <vector>
#include <map>
#include <queue>
#include <ctime>
#include <set>
#include <deque>
#include <string>
#define MP make_pair
#define PB push_back
#define SZ(x) ((int)(x).size())
#define REP(i,n) for (int _n=n,i=0; (i)<_n; ++(i))
#define FOR(i,a,b) for (int _b=b,i=(a);i<=_b;++(i))
#define FOREACH(it,c) for ( __typeof((c).begin()) it=(c).begin(),ite=(c).end(); it!=ite; ++it )
int rint() { int x; if(~scanf("%d",&x)) return x; return -1; }
typedef long long LL;
const int inf=~0U>>1;
using namespace std;

const int maxN=1010;
int t,n,m,dx[]={-1,1,0,0},dy[]={0,0,-1,1},sx,sy,ft[maxN][maxN];
char s[maxN][maxN];
bool vis[maxN][maxN];
struct Node{
	int time,x,y;
	Node(){}
	Node(int _time,int _x,int _y):time(_time),x(_x),y(_y){}
}no;
queue<Node> q;

int main(){
	t=rint();
	while(t--){
		n=rint(),m=rint();
		REP(i,n) scanf("%s",s[i]);
		memset(ft,-1,sizeof(ft));
		REP(i,n) REP(j,m) {
			if(s[i][j]=='F') ft[i][j]=0,q.push(Node(0,i,j));
			else if(s[i][j]=='J') sx=i,sy=j;
		}
		while(!q.empty()){
			no=q.front();
			q.pop();
			REP(i,4){
				int nx=no.x+dx[i],ny=no.y+dy[i];
				if(nx<0||nx>=n||ny<0||ny>=m||s[nx][ny]=='#') continue;
				if(ft[nx][ny]!=-1) continue;
				ft[nx][ny]=no.time+1;
				q.push(Node(ft[nx][ny],nx,ny));
			}
		}/*
		REP(i,n){
			REP(j,m) cout<<ft[i][j]<<" ";
			puts("");
		}*/
		memset(vis,false,sizeof(vis));
		int ans=-1;
		q.push(Node(0,sx,sy));
		vis[sx][sy]=true;
		while(!q.empty()){
			no=q.front();
			q.pop();
			if(ans!=-1) continue;
			REP(i,4){
				int nx=no.x+dx[i],ny=no.y+dy[i];
				if(nx<0||nx>=n||ny<0||ny>=m){
					ans=no.time+1;
					break;
				}
				if(s[nx][ny]=='#'||vis[nx][ny]) continue;
				vis[nx][ny]=true;
				if(ft[nx][ny]<=no.time+1) continue;
				q.push(Node(no.time+1,nx,ny));
			}
		}
		if(ans==-1) puts("IMPOSSIBLE");
		else cout<<ans<<endl;
	}
	return 0;
}

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