bfs
题目链接http://qscoj.cn/problem/37/
标准的bfs模型，就直接贴代码了。
1 #include <iostream> 2 #include <queue> 3 #include <cstring> 4 using namespace std; 5 const int maxn = 1e3+10; 6 int n, m, x1, x2, y1, y2; 7 typedef pair<int, int> P; 8 string s[maxn]; 9 int d[maxn][maxn]; 10 int dx[] = {1, 0, -1, 0}; 11 int dy[] = {0, 1, 0, -1}; 12 13 void solve(){ 14 x1--;x2--;y1--;y2--; 15 for(int i = 0; i < n; i ++) cin >> s[i]; 16 memset(d, -1, sizeof(d)); 17 queue<P> que; 18 que.push(P(x1,y1)); 19 d[x1][y1] = 0; 20 while(que.size()){ 21 P p = que.front();que.pop(); 22 if(p.first == x2 && p.second == y2)break; 23 for(int i = 0; i < 4; i++){ 24 int nx = p.first + dx[i], ny = p.second + dy[i]; 25 if(0 <= nx && nx < n && 0 <= ny && ny < m && s[nx][ny] != '0' && d[nx][ny] == -1){ 26 que.push(P(nx, ny)); 27 d[nx][ny] = d[p.first][p.second] + 1; 28 } 29 } 30 } 31 printf("%d\n",d[x2][y2]); 32 return; 33 } 34 35 int main(){ 36 while(cin>>n>>m>>x1>>y1>>x2>>y2) 37 solve(); 38 return 0; 39 }
