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

 

#include <cstdio>
#include <cstring>
#include <queue>
#include <cmath>
#include <algorithm>
#include <set>
#include <iostream>
#include <map>
#include <stack>
#include <string>
#include <vector>
#define pi acos(-1.0)
#define eps 1e-6
#define fi first
#define se second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define bug         printf("******
")
#define mem(a,b)    memset(a,b,sizeof(a))
#define fuck(x)     cout<<"["<<x<<"]"<<endl
#define f(a)        a*a
#define sf(n)       scanf("%d", &n)
#define sff(a,b)    scanf("%d %d", &a, &b)
#define sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
#define pf          printf
#define FRE(i,a,b)  for(i = a; i <= b; i++)
#define FREE(i,a,b) for(i = a; i >= b; i--)
#define FRL(i,a,b)  for(i = a; i < b; i++)
#define FRLL(i,a,b) for(i = a; i > b; i--)
#define FIN freopen("DATA.txt","r",stdin)
#define lowbit(x)   x&-x
#pragma comment (linker,"/STACK:102400000,102400000")

using namespace std;
const int maxn = 1e5 + 10;
typedef long long LL;
LL n,m,k;
int main() {
    while(~sfff(n,m,k)){
        k=k/2;
        LL ans=0;
        for (int i=1 ;i<=n ;i++) {
            if (k-i<=0) break;
            LL  a=(n-i+1);
            LL  b=min(k-i,m);
            LL  c=(m+(m-b+1))*b/2;
            ans+=a*c;
        }
        printf("%lld
",ans);
    }
    return 0;
}