HDU 3729 - I'm Telling the Truth

 1 /*
 2 ID:esxgx1
 3 LANG:C++
 4 PROG:hdu3729
 5 */
 6 #include <cstdio>
 7 #include <cstring>
 8 #include <iostream>
 9 #include <stack>
10 #include <algorithm>
11 using namespace std;
12 
13 #define NSTU    67
14 #define NRANK    1000009
15 
16 
17 pair<int, int> stu[NSTU];
18 char visited[NRANK];
19 int matched[NRANK];
20 
21 int aug(int s)
22 {
23     for(int t = stu[s].first; t<= stu[s].second; ++t) {
24         if (!visited[t]) {
25             visited[t] = 1;
26             if (matched[t] < 0 || aug(matched[t])) {
27                 matched[t] = s;
28                 return 1;
29             }
30         }
31     }
32     return 0;
33 }
34 
35 int main(void)
36 {
37     #ifndef ONLINE_JUDGE
38     freopen("in.txt", "r", stdin);
39     #endif
40 
41     int T;
42     for(scanf("%d", &T); T; --T) {
43         int N;
44         scanf("%d", &N);
45         if(!N) {
46             printf("0\n\n");
47             continue;
48         }
49         for(int i=0; i<N; ++i) {
50             int x, y;
51             scanf("%d%d", &x, &y);
52             stu[i].first = x, stu[i].second = y;
53         }
54 
55         memset(matched, -1, sizeof(matched));
56 
57         int ans[NSTU], _top = 0;
58         for(int i=N-1; i>0; --i) {
59             if (aug(i))    ans[_top++] = i+1;
60             memset(visited, 0, sizeof(visited));
61         }
62         if (aug(0))    ans[_top++] = 1;
63         printf("%d\n", _top);
64         while(_top > 1) printf("%d ", ans[--_top]);
65         if (_top) printf("%d", ans[--_top]);
66         putchar(‘\n‘);
67     }
68     return 0;
69 }