标程: 广度优先搜索 BFS

贴个标程, 以方便查阅.

 

#include <iostream>#include <algorithm>#include <vector>#include <queue>using namespace std;int maze[40][40];int w, h;int startx,starty, exitx, exity;int dx[] = {-1, 0, 1, 0};int dy[] = {0, -1, 0, 1};struct Point{int x, y;Point(int xx, int yy){x = xx; y = yy;}};bool ok(int x, int y){if(x < 0 || x >= w || y < 0 || y >= h)return false;return (maze[y][x]==1 || maze[y][x] == 3);}bool visited[40][40];int step[40][40];int bfs(int x, int y){memset(visited, 0, sizeof(visited));memset(step, 0, sizeof(step));queue<Point> q;q.push(Point(x, y));visited[y][x] = true;int cnt = 0;while(!q.empty()){Point p = q.front();if(p.x == exitx && p.y == exity)break;q.pop();for(int i = 0; i < 4; ++i){int tempx = p.x+dx[i], tempy = p.y+dy[i];if(ok(tempx, tempy) && !visited[tempy][tempx]){step[tempy][tempx] = step[p.y][p.x] + 1;q.push(Point(tempx, tempy));visited[tempy][tempx] = true;}}}return step[exity][exitx]+1;}

 

再贴个别人非stl实现的.

 

#include <iostream>#include <string.h>using namespace std;int step[501][501];int visited[501][501];int startx,starty,endx,endy,m,n;struct Node{ int x; int y;} que[250001];void bfs(){ int direct[8][2]={{1,2},{2,1},{-1,-2},{-2,-1},{-1,2},{2,-1},{1,-2},{-2,1}}; int front=-1,rear=-1,curx,cury,tempx,tempy,i; que[++rear].x=startx; que[rear].y=starty; step[startx][starty]=0; visited[startx][starty]=1; while(front!=rear) { curx=que[++front].x; cury=que[front].y; if((curx==endx)&&(cury==endy)) break; for(i=0;i<8;i++) { tempx=curx+direct[i][0]; tempy=cury+direct[i][1]; if(tempx>0&&tempx<=m&&tempy>0&&tempy<=n&&visited[tempx][tempy]==0) { step[tempx][tempy]=step[curx][cury]+1; visited[tempx][tempy]=1; que[++rear].x=tempx; que[rear].y=tempy; } } }} int main(){ int k; cin>>k; while(k--) { memset(step,0,sizeof(step)); memset(visited,0,sizeof(visited)); cin>>m>>n; cin>>startx>>starty>>endx>>endy; bfs(); cout<<step[endx][endy]<<endl; } return 0;}