C++14(g++5.4) 解法, 执行用时: 459ms, 内存消耗: 6764K, 提交时间: 2019-09-10 23:01:03

//https://ac.nowcoder.com/acm/contest/275/G
#include<bits/stdc++.h>
using namespace std;
#define ll long long 
const int mod=1e9+7;
const int N=1e5+100; 
ll a[N];
ll c[N],p[N],ans[N];
int n,m,k;
struct edge
{
	int l,r;
	ll w;
	bool operator<(const edge &x)const 
	{
		return r<x.r;
	}
}e[N];
struct node
{
	int l,r,id;
	bool operator<(const node &x) const 
	{
		return r<x.r;
	}
}q[N];
ll qpow(ll a,ll b)
{
	ll ans=1;
	while(b)
	{
		if(b&1) ans=(ans*a)%mod;
		a=a*a%mod;
		b>>=1;
	}
	return ans;
}
void add(int x,ll v)
{
	while(x<=n)
	{
		c[x]=(c[x]+v)%mod;
		x+=x&-x;
	}
}
ll getsum(int x)
{
	ll ans=0;
	while(x)
	{
		ans=(ans+c[x])%mod;
		x-=x&-x;
	}
	return ans;
}
int main()
{
	cin>>n>>m>>k;
	for(int i=1;i<=n;i++)
	{
		ll x,y;
		cin>>x>>y;
		a[i]=x*qpow(y,mod-2)%mod;
		p[i]=(p[i-1]+a[i])%mod;
	}
	for(int i=1;i<=m;i++)
	{
		cin>>e[i].l>>e[i].r;
		if(e[i].l>e[i].r) swap(e[i].l,e[i].r);
		e[i].w=a[e[i].l]*a[e[i].r]%mod;
	}
	for(int i=1;i<=k;i++) cin>>q[i].l>>q[i].r,q[i].id=i;
	sort(q+1,q+1+k);
	sort(e+1,e+m+1);
	int j=1;
	for(int i=1;i<=k;i++)
	{
		while(j<=m&&e[j].r<=q[i].r)
		{
			add(e[j].l,e[j].w);
			j++;
		}
		ll x=(getsum(q[i].r)-getsum(q[i].l-1)+mod)%mod;
		ans[q[i].id]=(p[q[i].r]-p[q[i].l-1]+mod-x+mod)%mod;
	}
	for(int i=1;i<=k;i++)  cout<<ans[i]<<endl;
	return 0;
}

C++ 解法, 执行用时: 121ms, 内存消耗: 11668K, 提交时间: 2021-11-27 17:08:21

#include<bits/stdc++.h>
using namespace std;

const int mod=1e9+7;
struct node
{
	int l,r,id;
}Q[100005];
bool cmp(node a,node b)
{
	return a.r<b.r;
}
vector<int>R[100005],W[100005];
int i,j,k,n,m,q,P[100005],S[100005]={0},pre[100005]={0},ans[100005];
long long fastpow(long long a,int b)
{
	long long s=1;
	for(;b;b>>=1,a=a*a%mod)if(b&1)s=s*a%mod;
	return s;
}
int lowbit(int x)
{
	return x&(-x);
}
void update(int i,int x)
{
	while(i<=n)S[i]=(S[i]+x)%mod,i+=lowbit(i);
}
long long getsum(int i)
{
	int s=0;
	while(i)s=(s+S[i])%mod,i-=lowbit(i);
	return s;
}
int main()
{
    scanf("%d%d%d",&n,&m,&q);
    for(i=1;i<=n;i++)
    {
    	scanf("%d%d",&j,&k);
		P[i]=j*fastpow(k,mod-2)%mod,pre[i]=(pre[i-1]+P[i])%mod;
	}
    while(m--)
    {
    	scanf("%d%d",&i,&j);
    	if(i<j)swap(i,j);
    	R[i].push_back(j),W[i].push_back((long long)P[i]*P[j]%mod); 
	}
	for(i=0;i<q;i++)scanf("%d%d",&Q[i].l,&Q[i].r),Q[i].id=i;
	sort(Q,Q+q,cmp);
	for(i=1,j=0;i<=n;i++)
	{
		for(k=0;k<R[i].size();k++)update(R[i][k],W[i][k]);
		for(;j<q&&Q[j].r<=i;j++)ans[Q[j].id]=(pre[i]-pre[Q[j].l-1]-getsum(i)+getsum(Q[j].l-1)+2*mod)%mod;
	}
	for(i=0;i<q;i++)printf("%d\n",ans[i]);
    return 0;
}