【HDOJ】5203 Rikka with wood sticks

 1 /* 1002 */
 2 #include <iostream>
 3 #include <string>
 4 #include <map>
 5 #include <queue>
 6 #include <set>
 7 #include <stack>
 8 #include <vector>
 9 #include <algorithm>
10 #include <cstdio>
11 #include <cmath>
12 #include <ctime>
13 #include <cstring>
14 #include <climits>
15 #include <cctype>
16 using namespace std;
17
18 const int maxn = 1e3+5;
19
20 int a[maxn], dis[maxn];
21 int n, m;
22
23 int main() {
24     int i, j, k;
25     int mx, q;
26     int l1, l2;
27     int x, y, z, s, tmp;
28     __int64 ans;
29     int L, R;
30
31     #ifndef ONLINE_JUDGE
32         freopen("data.in", "r", stdin);
33         freopen("data.out", "w", stdout);
34     #endif
35
36     while (scanf("%d %d", &n, &m) != EOF) {
37         R = -1;
38         L = n+1;
39         ans = 0;
40         for (i=1; i<=m; ++i) {
41             scanf("%d", &a[i]);
42             L = min(a[i], L);
43             R = max(a[i], R);
44         }
45         if (L==1 || R==n) {
46             s = max(L-1, n-R);
47             for (z=1; z<n; ++z) {
48                 if (z >= s-z)
49                     break;
50                 tmp = s-z;
51                 L = (tmp-z)/2+1;
52                 R = (tmp+z-1)/2;
53                 ans += (R-L+1);
54             }
55             printf("%I64d\n", ans);
56             continue;
57         }
58         l1 = L-1;
59         l2 = n-R;
60         z = l1;
61         for (x=1; x<l2; ++x) {
62             y = l2-x;
63             if (x+y>z && y+z>x && z+x>y)
64                 ++ans;
65         }
66         z = l2;
67         for (x=1; x<l1; ++x) {
68             y = l1-x;
69             if (x+y>z && y+z>x && z+x>y)
70                 ++ans;
71         }
72         printf("%I64d\n", ans);
73     }
74
75     #ifndef ONLINE_JUDGE
76         printf("%d\n", (int)clock());
77     #endif
78
79     return 0;
80 }