HDU1026 (BFS)
题意:从起点到终点,输出路径长度,时间。
bfs+记录路径
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
1 #include<stdio.h> 2 #include<string.h> 3 #include<stdlib.h> 4 #include<queue> 5 const int N = 105; 6 const int inf = 9999999; 7 using namespace std; 8 9 struct node{ 10 int x,y; 11 }; 12 node p,pp,path[N][N]; 13 struct node2{ 14 int x1,y1,x2,y2; 15 }out[1000005]; 16 17 char map[N][N]; 18 int time[N][N]; 19 int n,m,endflag,ans; 20 queue<node>q; 21 22 const int dx[]={1,-1,0,0}; 23 const int dy[]={0,0,1,-1}; 24 25 void init(){ 26 for(int i=0;i<N;i++) 27 for(int j=0;j<N;j++){ 28 path[i][j].x=-1; 29 path[i][j].y=-1; 30 time[i][j]=inf; 31 } 32 } 33 34 bool judge(int x,int y){ 35 if(map[x][y]>='1'&&map[x][y]<='9') 36 return true; 37 return false; 38 } 39 40 void output(){ 41 int nowx,nowy,tpx,tpy,cnt=1; 42 nowx=n-1; 43 nowy=m-1; 44 while(nowx!=0||nowy!=0){ 45 out[cnt].x1=path[nowx][nowy].x; 46 out[cnt].y1=path[nowx][nowy].y; 47 out[cnt].x2=nowx; 48 out[cnt++].y2=nowy; 49 tpx=nowx; 50 tpy=nowy; 51 nowx=path[tpx][tpy].x; 52 nowy=path[tpx][tpy].y; 53 } 54 55 int cnt2=1; 56 for(int i=cnt-1;i>=1;i--) 57 { 58 if(judge(out[i].x1,out[i].y1)==false) 59 printf("%ds:(%d,%d)->(%d,%d)\n",cnt2++,out[i].x1,out[i].y1,out[i].x2,out[i].y2); 60 else 61 { 62 int pp; 63 pp=map[out[i].x1][out[i].y1]-'0'; 64 for(int j=1;j<=pp;j++) 65 printf("%ds:FIGHT AT (%d,%d)\n",cnt2++,out[i].x1,out[i].y1); 66 printf("%ds:(%d,%d)->(%d,%d)\n",cnt2++,out[i].x1,out[i].y1,out[i].x2,out[i].y2); 67 } 68 } 69 if(endflag!=-1){ 70 int pp; 71 pp=endflag; 72 for(int j=1;j<=pp;j++) 73 printf("%ds:FIGHT AT (%d,%d)\n",cnt2++,n-1,m-1); 74 } 75 printf("FINISH\n"); 76 } 77 78 void bfs(){ 79 int i,j,k; 80 ans=inf; 81 endflag=-1; 82 while(!q.empty())q.pop(); 83 p.x=0; 84 p.y=0; 85 time[p.x][p.y]=0; 86 if(judge(0,0)==true) 87 time[0][0]=map[0][0]-'0'; 88 q.push(p); 89 while(!q.empty()){ 90 p=q.front(); 91 q.pop(); 92 93 if(p.x==n-1&&p.y==m-1) 94 if(time[n-1][m-1]<ans) 95 ans=time[n-1][m-1]; 96 97 for(i=0;i<4;i++){ 98 pp.x=p.x+dx[i]; 99 pp.y=p.y+dy[i]; 100 if(pp.x<0||pp.x>=n||pp.y<0||pp.y>=m) 101 continue; 102 if(map[pp.x][pp.y]=='X') 103 continue; 104 if(map[pp.x][pp.y]=='.'&&time[pp.x][pp.y]>(time[p.x][p.y]+1)){ 105 time[pp.x][pp.y]=time[p.x][p.y]+1; 106 path[pp.x][pp.y].x=p.x; 107 path[pp.x][pp.y].y=p.y; 108 q.push(pp); 109 } 110 if(map[pp.x][pp.y]>='1'&&map[pp.x][pp.y]<='9'){ 111 if(time[pp.x][pp.y]>(time[p.x][p.y]+map[pp.x][pp.y]-'0'+1)){ 112 time[pp.x][pp.y]=time[p.x][p.y]+map[pp.x][pp.y]-'0'+1; 113 path[pp.x][pp.y].x=p.x; 114 path[pp.x][pp.y].y=p.y; 115 if(pp.x==n-1&&pp.y==m-1){ 116 endflag=map[pp.x][pp.y]-'0'; 117 } 118 q.push(pp); 119 } 120 } 121 } 122 } 123 124 if(ans!=inf){ 125 printf("It takes %d seconds to reach the target position, let me show you the way.\n",ans); 126 output(); 127 } 128 else 129 printf("God please help our poor hero.\nFINISH\n"); 130 return ; 131 } 132 133 int main(){ 134 int i; 135 while( scanf("%d%d",&n,&m)!=EOF ){ 136 memset(map,0,sizeof(map)); 137 for(i=0;i<n;i++) 138 scanf("%s",map[i]); 139 init(); 140 bfs(); 141 } 142 return 0; 143 }
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