Language: C++

#include<bits/stdc++.h>
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define REP(i,n) for(int i=0;i<int(n);i++)
#define fi first
#define se second
#define pb push_back
#define mp make_pair
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef long long ll;

template<class T> void read(T &x){
	int f=0; x=0; char ch=getchar();
	for(;!isdigit(ch);ch=getchar()) f|=(ch=='-');
	for(;isdigit(ch);ch=getchar()) x=x*10+ch-'0';
	if(f) x=-x;
}

const int N=5005,mod=1e9+7,inv2=(mod+1)/2;
int f[N][N],s[N][N],sa[N][N],sb[N][N],sab[N][N];
int ipw[N],pw[N];
int n,m,ans;

int power(int x,int p){
	int res=1;
	for(;p;p>>=1,x=(ll)x*x%mod)
		if(p&1) res=(ll)res*x%mod;
	return res;
}
int mul(int x,int y){
	return (ll)x*y%mod;
}
void add(int &x,int y){
	x=(x+y>=mod?x+y-mod:x+y);
}
int pw(int x){
	return x>=mod?pw[x]:ipw[-x];
}

int main(){
	read(n),read(m);
	pw[0]=ipw[0]=1;
	rpe(i,1,5000){
		pw[i]=mul(pw[i-1],2);
		ipw[i]=mul(ipw[i-1],inv2);
	}
	rep(i,0,n) rep(j,0,m){
		if(i==0){
			if(j==0) f[i][j]=1;
		}
		else if(j){
			f[i][j]=mul(s[i-1][j-1],mod-j+1);
			add(f[i][j],mul(sa[i-1][j-1],mul(pw(i-1),mod-b)));
			add(f[i][j],mul(sb[i-1][j-1]));
			add(f[i][j],mul(sab[i-1][j-1],mod-pw(i-1)));
		}
		else{
			f[i][j]=1;
		}
		s[i][j]=f[i][j];
		if(i) add(s[i][j],mod-s[i-1][j]);
		if(j) add(s[i][j],mod-s[i][j-1]);
		if(i&&j) add(s[i][j],s[i-1][j-1]);
		sa[i][j]=mul(f[i][j],pw(-i));
		if(i) add(sa[i][j],mod-sa[i-1][j]);
		if(j) add(sa[i][j],mod-sa[i][j-1]);
		if(i&&j) add(sa[i][j],sa[i-1][j-1]);
		sb[i][j]=mul(f[i][j],j);
		if(i) add(sb[i][j],mod-sb[i-1][j]);
		if(j) add(sb[i][j],mod-sb[i][j-1]);
		if(i&&j) add(sb[i][j],sb[i-1][j-1]);
		sab[i][j]=mul(f[i][j],mul(pw(-i),j));
		if(i) add(sab[i][j],mod-sab[i-1][j]);
		if(j) add(sab[i][j],mod-sab[i][j-1]);
		if(i&&j) add(sab[i][j],sab[i-1][j-1]);
	}
	int ans=0;
	rep(i,0,m) add(ans,f[n][i]);
	cout<<ans<<endl;

	return 0;
}

Compiler output:
a.cc:38:13: error: 'int pw(int)' redeclared as different kind of entity
   38 | int pw(int x){
      |             ^
a.cc:23:12: note: previous declaration 'int pw [5005]'
   23 | int ipw[N],pw[N];
      |            ^~
a.cc: In function 'int main()':
a.cc:45:13: error: 'i' was not declared in this scope; did you mean 'vi'?
   45 |         rpe(i,1,5000){
      |             ^
      |             vi
a.cc:45:9: error: 'rpe' was not declared in this scope; did you mean 'rep'?
   45 |         rpe(i,1,5000){
      |         ^~~
      |         rep
a.cc:55:60: error: 'pw' cannot be used as a function
   55 |                         add(f[i][j],mul(sa[i-1][j-1],mul(pw(i-1),mod-b)));
      |                                                          ~~^~~~~
a.cc:55:70: error: 'b' was not declared in this scope
   55 |                         add(f[i][j],mul(sa[i-1][j-1],mul(pw(i-1),mod-b)));
      |                                                                      ^
a.cc:56:40: error: too few arguments to function 'int mul(int, int)'
   56 |                         add(f[i][j],mul(sb[i-1][j-1]));
      |                                     ~~~^~~~~~~~~~~~~~
a.cc:32:5: note: declared here
   32 | int mul(int x,int y){
      |     ^~~
a.cc:57:61: error: 'pw' cannot be used as a function
   57 |                         add(f[i][j],mul(sab[i-1][j-1],mod-pw(i-1)));
      |                                                           ~~^~~~~
a.cc:66:40: error: 'pw' cannot be used as a function
   66 |                 sa[i][j]=mul(f[i][j],pw(-i));
      |                                      ~~^~~~
a.cc:74:45: error: 'pw' cannot be used as a function
   74 |                 sab[i][j]=mul(f[i][j],mul(pw(-i),j));
      |                                           ~~^~~~