Codeforces Round #645 (Div. 2) C

想明白之后就是，路径条数

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll a,b,c,d;
inline ll read()
{
    ll x=0,w=1;
    char c=getchar();
    while(c<'0'||c>'9')
    {
        if(c=='-') w=-1;
        c=getchar();
    }
    while(c<='9'&&c>='0')
    {
        x=(x<<1)+(x<<3)+c-'0';
        c=getchar();
    }
    return w==1?x:-x;
}
int main()
{
    int T=read();
    while(T--)
    {
        ll a=read(),b=read(),c=read(),d=read();
        ll dx=abs(a-c);
        ll dy=abs(b-d);
        ll ans=dx*dy+1;
        cout<<ans<<endl;
    }
    return 0;
}