Language: C++

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define nn 3000008
#define mod 1000000007
int qpow(int x,int y=mod-2){
	int res=1;while(y){
		if(y&1) res=res*x%mod;
		x=x*x%mod;y=y/2;
	}
	return res;
}
int f[nn],rf[nn];
int C(int n,int m){
	return f[n]*rf[m]%mod*rf[n-m]%mod;
}
int y2[2],x2[2];
int go(int x,int y){
	if(x<0 or y<0) return 0;
	return C(x+y,x);
}
int solve(int x1,int y1,int x3,int y3){
	int ans=0;
	for(int i=y2[0];i<=y2[1];i++){
		ans-=(i-y1+x2[0]-x1-1)*go(x2[0]-x1-1,i-y1)%mod*go(x3-x2[0],y3-i)%mod;
		ans+=(i-y1+x2[1]-x1)*go(x2[1]-x1,i-y1)%mod*go(x3-1-x2[1],y3-i)%mod;
	}
	for(int i=x2[0];i<=x2[1];i++){
		ans-=(i-x1+y2[0]-y1-1)*go(i-x1,y2[0]-y1-1)%mod*go(x3-i,y3-y2[0])%mod;
		ans+=(i-x1+y2[1]-y1)*go(i-x1,y2[1]-y1)%mod*go(x3-i,y3-1-y2[1])%mod;
	}
	return ans%mod;
}
int x1[2],x3[2],y1[2],y3[2];
void in(int a[]){
	for(int i=0;i<2;i++) scanf("%lld",&a[i]);
}
signed main(){
	f[0]=1;for(int i=1;i<nn;i++) f[i]=f[i-1]*i%mod;
	rf[nn-1]=qpow(f[nn-1]);
	for(int i=nn-2;i>=0;i--) rf[i]=rf[i+1]*(i+1)%mod;
	
	in(x1);in(x2);in(x3);in(y1);in(y2);in(y3);	
//	x1[0]--,y1[0]--;
//	x3[1]++,y3[1]++;
		
	int ans=0;
	for(int i=x1[0];i<=x1[1];i++) for(int j=y1[0];j<=y1[1];j++)
		for(int k=x3[0];k<=x3[1];k++) for(int l=y3[0];l<=y3[1];l++)
			ans+=solve(i,j,k,l);
	
//	for(int i=0;i<2;i++) for(int j=0;j<2;j++) for(int k=0;k<2;k++) for(int l=0;l<2;l++){
//		int ret=solve(x1[i],y1[j],x3[k],y3[l]);
//		if(i^j^k^l) ans-=ret;else ans+=ret;ans%=mod;
//	}
	ans+=mod;ans%=mod;printf("%lld\n",ans);
	return 0;
}

Compiler output:
a.cc:34:21: error: 'long long int y1 [2]' redeclared as different kind of entity
   34 | int x1[2],x3[2],y1[2],y3[2];
      |                     ^
In file included from /usr/include/features.h:523,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/c++config.h:683,
                 from /usr/include/c++/14/cassert:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:33,
                 from a.cc:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:257:1: note: previous declaration 'double y1(double)'
  257 | __MATHCALL (y1,, (_Mdouble_));
      | ^~~~~~~~~~
a.cc: In function 'int main()':
a.cc:43:32: error: cannot convert 'double (*)(double) noexcept' to 'long long int*'
   43 |         in(x1);in(x2);in(x3);in(y1);in(y2);in(y3);
      |                              ~~^~~~
      |                                |
      |                                double (*)(double) noexcept
a.cc:35:13: note:   initializing argument 1 of 'void in(long long int*)'
   35 | void in(int a[]){
      |             ^
a.cc:48:53: warning: pointer to a function used in arithmetic [-Wpointer-arith]
   48 |         for(int i=x1[0];i<=x1[1];i++) for(int j=y1[0];j<=y1[1];j++)
      |                                                     ^
a.cc:48:53: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   48 |         for(int i=x1[0];i<=x1[1];i++) for(int j=y1[0];j<=y1[1];j++)
      |                                                     ^
      |                                                     |
      |                                                     double (*)(double) noexcept
a.cc:48:62: warning: pointer to a function used in arithmetic [-Wpointer-arith]
   48 |         for(int i=x1[0];i<=x1[1];i++) for(int j=y1[0];j<=y1[1];j++)
      |                                                              ^
a.cc:48:56: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   48 |         for(int i=x1[0];i<=x1[1];i++) for(int j=y1[0];j<=y1[1];j++)
      |                                                       ~^~~~~~~