codeforces #630 E. A rectangle 【数学】

题目链接

推公式就好了，注意爆int

#include<iostream>#include<cstdio>#include<cmath>#include<algorithm>#include<cstring>using namespace std;int main(){    long long x0,y0,x,y;    cin>>x0>>y0>>x>>y;    cout<<((x-x0)/2+1)*((y-y0)/2+1)+(x-x0)*(y-y0)/4<<endl;    return 0;}