pku 2488 A Knight's Journey DFS

经典DFS.

#include <iostream>#include <algorithm>#include <vector>using namespace std;int dx[] = {-1, 1, -2, 2, -2, 2, -1, 1};int dy[] = {-2, -2, -1, -1, 1, 1, 2, 2};bool visited[9][9];int path1[64], path2[64];int width, height;bool bOk;inline bool ok(int x, int y, int dx, int dy){if(x+dx<1 || x+dx>width || y+dy<1 || y+dy>height)return false;return true;}void dfs(int x, int y, int n){if(n == width*height-1){bOk = true;return;}for(int i = 0; !bOk && i < 8; ++i)if(ok(x, y, dx[i], dy[i]) && !visited[x+dx[i]][y+dy[i]]){visited[x+dx[i]][y+dy[i]] = true;path1[n] = x+dx[i], path2[n] = y+dy[i];dfs(x+dx[i], y+dy[i], n+1);visited[x+dx[i]][y+dy[i]] = false;}}int main(){int cnt;scanf("%d", &cnt);for(int n = 1; n <= cnt; ++n){scanf("%d%d", &width, &height);printf("Scenario #%d:/n", n);if(width == 1 && height == 1){printf("A1/n/n");continue;}memset(visited, 0, sizeof(visited));memset(path1, 0, sizeof(path1));memset(path2, 0, sizeof(path2));bOk = false;visited[1][1] = true;dfs(1, 1, 0);if(bOk){printf("A1");for(int i = 0; i < width*height-1; ++i)printf("%c%d", path2[i]+'A'-1, path1[i]);printf("/n/n");}elseprintf("impossible/n/n");}return 0;}