CF-242-C bfs+stl

 1 #include <iostream>
 2 #include <cstring>
 3 #include <cstdio>
 4 #include <queue>
 5 #include <set>
 6 using namespace std;
 7 
 8 typedef pair<int, int> pii;
 9 set<pii> s;
10 queue< pair<pii, int> > q;
11 int dx[] = { 0, 0, 1, -1, 1, 1, -1, -1 };
12 int dy[] = { 1, -1, 0, 0, 1, -1, 1, -1 };
13 
14 int main ()
15 {
16     int x0, y0, x1, y1;
17     while ( scanf("%d%d%d%d", &x0, &y0, &x1, &y1) != EOF )
18     {
19         s.clear();
20         while ( !q.empty() ) q.pop();
21         int t;
22         scanf("%d", &t);
23         while ( t-- )
24         {
25             int r, a, b;
26             scanf("%d%d%d", &r, &a, &b);
27             for ( int k = a; k <= b; k++ )
28             {
29                 s.insert( make_pair( r, k ) );
30             }
31         }
32         q.push( make_pair( make_pair( x0, y0 ), 0 ) );
33         int ans = -1;
34         while ( !q.empty() )
35         {
36             int x = q.front().first.first;
37             int y = q.front().first.second;
38             int step = q.front().second;
39             q.pop();
40             if ( x == x1 && y == y1 )
41             {
42                 ans = step;
43                 break;
44             }
45             for ( int i = 0; i < 8; i++ )
46             {
47                 pii tmp( x + dx[i], y + dy[i] );
48                 if ( s.find( tmp ) == s.end() ) continue;
49                 s.erase(tmp);
50                 q.push( make_pair( tmp, step + 1 ) );
51             }
52         }
53         printf("%d\n", ans);
54     }
55     return 0;
56 }