CF630E Solution

题目链接

题解

推式子呐，设\(x_2-x_1=x,y_2-y_1=y\)，\(ans=\frac{y+2}{2}\cdot(x+1)-\frac{x+1}{2}\)。以题目样例为例，六边形个数\(=5\)（列数）\(\times 3\)（奇数列每列个数）\(-2\)（偶数列个数）。

AC代码

#include<bits/stdc++.h>
#define int long long
using namespace std;
signed main()
{
	int x1,y1,x2,y2;
	scanf("%lld%lld%lld%lld",&x1,&y1,&x2,&y2);
	printf("%lld",(y2-y1+2)/2*(x2-x1+1)-(x2-x1+1)/2);
	return 0;
}