【HDOJ】5203 Rikka with wood sticks

 /* 1002 */
 #include <iostream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 using namespace std;

 const int maxn = 1e3+;

 int a[maxn], dis[maxn];
 int n, m;

 int main() {
     int i, j, k;
     int mx, q;
     int l1, l2;
     int x, y, z, s, tmp;
     __int64 ans;
     int L, R;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     while (scanf("%d %d", &n, &m) != EOF) {
         R = -;
         L = n+;
         ans = ;
         for (i=; i<=m; ++i) {
             scanf("%d", &a[i]);
             L = min(a[i], L);
             R = max(a[i], R);
         }
         if (L== || R==n) {
             s = max(L-, n-R);
             for (z=; z<n; ++z) {
                 if (z >= s-z)
                     break;
                 tmp = s-z;
                 L = (tmp-z)/+;
                 R = (tmp+z-)/;
                 ans += (R-L+);
             }
             printf("%I64d\n", ans);
             continue;
         }
         l1 = L-;
         l2 = n-R;
         z = l1;
         for (x=; x<l2; ++x) {
             y = l2-x;
             if (x+y>z && y+z>x && z+x>y)
                 ++ans;
         }
         z = l2;
         for (x=; x<l1; ++x) {
             y = l1-x;
             if (x+y>z && y+z>x && z+x>y)
                 ++ans;
         }
         printf("%I64d\n", ans);
     }

     #ifndef ONLINE_JUDGE
         printf("%d\n", (int)clock());
     #endif

     return ;
 }