Rectangle 暴力枚举大法

frog has a piece of paper divided into  n rows and m columns. Today, she would like to draw a rectangle whose perimeter is not greater than k.

 

 

There are  8 (out of 9) ways when n=m=2,k=6

 

Find the number of ways of drawing.

 

 

 

枚举长度  然后算出宽度的取值范围  对宽带再进行求合

 

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <queue>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <set>
 7 #include <iostream>
 8 #include <map>
 9 #include <stack>
10 #include <string>
11 #include <vector>
12 #define pi acos(-1.0)
13 #define eps 1e-6
14 #define fi first
15 #define se second
16 #define lson l,m,rt<<1
17 #define rson m+1,r,rt<<1|1
18 #define bug         printf("******\n")
19 #define mem(a,b)    memset(a,b,sizeof(a))
20 #define fuck(x)     cout<<"["<<x<<"]"<<endl
21 #define f(a)        a*a
22 #define sf(n)       scanf("%d", &n)
23 #define sff(a,b)    scanf("%d %d", &a, &b)
24 #define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
25 #define pf          printf
26 #define FRE(i,a,b)  for(i = a; i <= b; i++)
27 #define FREE(i,a,b) for(i = a; i >= b; i--)
28 #define FRL(i,a,b)  for(i = a; i < b; i++)
29 #define FRLL(i,a,b) for(i = a; i > b; i--)
30 #define FIN freopen("DATA.txt","r",stdin)
31 #define lowbit(x)   x&-x
32 #pragma comment (linker,"/STACK:102400000,102400000")
33 
34 using namespace std;
35 const int maxn = 1e5 + 10;
36 typedef long long LL;
37 LL n,m,k;
38 int main() {
39     while(~sfff(n,m,k)){
40         k=k/2;
41         LL ans=0;
42         for (int i=1 ;i<=n ;i++) {
43             if (k-i<=0) break;
44             LL  a=(n-i+1);
45             LL  b=min(k-i,m);
46             LL  c=(m+(m-b+1))*b/2;
47             ans+=a*c;
48         }
49         printf("%lld\n",ans);
50     }
51     return 0;
52 }