WA on #13~#20求条

#include<bits/stdc++.h>
#define int long long
using namespace std;
constexpr int maxm=1e5+5,mod=1e9+7;
int read(){
	int f=1,x=0;
	char ch=getchar();
	while (ch>'9' || ch<'0'){
		if (ch=='-') f*=-1;
		ch=getchar();
	}
	while (ch>='0' && ch<='9'){
		x=(x<<1)+(x<<3)+ch-'0';
		ch=getchar();
	}
	return f*x;
}
struct node{
	int c,d;
}p[maxm];
bool cmp(node a,node b){
	return a.c<b.c;
}
bool operator ==(node a,node b){
	return a.c==b.c && a.d==b.d;
}
int qpow(int a,int x){
	int res=1;
	while (x){
		if (x&1) res=res*a%mod;
		a=a*a%mod;x/=2;
	}
	return res%mod;
}
int T,n,m,v,ans;
signed main(){
	T=read();
	while (T--){
		bool flag=false;
		n=read(),m=read(),v=read();
		for (int i=1;i<=m;i++) 
			p[i].c=read(),p[i].d=read();
		sort(p+1,p+1+m,cmp);
		m=unique(p+1,p+1+m)-p-1;//去重
		int ans=qpow(v,2*(p[1].c-1+n-p[m].c));//两边
		for (int i=2;i<=m;i++){
			ans=(ans*(qpow(v,2*(p[i].c-p[i-1].c))-qpow(v,p[i].c-p[i-1].c-1)*(v-1)))%mod;//计算中间部分v^(2*(c[i]-c[i-1]))-v^(c[i]-c[i-1]-1)*(v-1)
			if (p[i-1].c==p[i].c && p[i-1].d!=p[i].d){
				cout/*<<"!"*/<<0<<'\n';
				flag=true;break;
			}
		}
		if (!flag) cout<<ans%mod<<'\n';
	}
	return 0;
}