我有以下代码，用于具有延迟传播的分段树，我可以设法编写。此代码不适用于将某个范围内的所有数字与一个值相乘，例如 x。我认为我在 update_mult 函数中做错了什么。树维护范围的总和。
我无法弄清楚 update_mult 的问题。专家，你能帮我找出我在实施中哪里出了问题吗？
#include <iostream>
#include <stdio.h>
#include <algorithm>
#include <stdlib.h>
#include <math.h>
#include <set>
#include <assert.h>
#include <cstring>
#include <string>
#include <string.h>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <time.h>
#include <climits>
using namespace std;
#define FOR(i,a,b) for(int i=a;i<b;++i)
#define FORR(i,a,b) for(int i=a;i>=b;--i)
#define FORC(it,container) for(typeof(container.begin()) it=container.begin();it!=container.end();++it)
#define INT(x) scanf("%d",&x)
#define LLD(x) scanf("%lld",&x)
#define STR(x) scanf("%s",x)
#define CHAR(x) scanf("%c",&x)
#define PINT(x) printf("%d\n",x)
#define PLLD(x) printf("%lld\n",x)
#define CLR(x) memset(x,0,sizeof(x));
const int INF = INT_MAX;
const int MAX = 1000001;
typedef long long LL;
LL arr[MAX+5];
LL MOD = 1e9 + 7;
struct data
{
LL sumsq;
LL sum;
LL lazyset;
LL setval;
LL lazyMult;
LL lazyVal;
LL addval;
void assignleaf()
{
}
void assignleaf(int idx ,int val)
{
}
void combine(data &l, data &r)
{
sum = (l.sum + r.sum)%MOD;
}
};
data tree[10*MAX+5];
void pushdown(int node,int segs,int sege)
{
int mid = segs+sege; mid /= 2;
if(tree[node].lazyset==1)
{
tree[node].lazyset=0;
tree[2*node].lazyset=1;
tree[2*node+1].lazyset=1;
tree[2*node].setval = tree[node].setval;
tree[2*node+1].setval = tree[node].setval;
tree[2*node].sum = ((mid-segs+1)*tree[node].setval)%MOD;
tree[2*node+1].sum = ((sege-mid)*tree[node].setval)%MOD;
tree[2*node].addval=0;
tree[2*node+1].addval=0;
}
if(tree[node].lazyMult==1)
{
tree[node].lazyMult=0;
tree[2*node].lazyMult=1;
tree[2*node+1].lazyMult=1;
tree[2*node].sum = (tree[2*node].sum * tree[node].lazyVal)%MOD;
tree[2*node+1].sum = (tree[2*node+1].sum * tree[node].lazyVal)%MOD;
tree[2*node].addval=0;
tree[2*node+1].addval=0;
}
if(tree[node].addval)
{
tree[2*node].addval = (tree[2*node].addval +tree[node].addval)%MOD;
tree[2*node+1].addval = (tree[2*node+1].addval +tree[node].addval)%MOD;
tree[2*node].sum = (tree[2*node].sum + ((mid-segs+1)*tree[node].addval)%MOD)%MOD;
tree[2*node+1].sum =(tree[2*node+1].sum+ ((sege-mid)*tree[node].addval)%MOD)%MOD;
tree[node].addval = 0;
}
}
void build_tree(int node,int s,int e)
{
tree[node].addval=0;
tree[node].lazyset=0;
if(s>e) return;
if(s==e)
{
tree[node].sum = arr[s];
return;
}
int mid=(s+e)/2;
build_tree(2*node,s,mid);
build_tree(2*node+1,mid+1,e);
tree[node].combine(tree[2*node],tree[2*node+1]);
}
LL query(int node,int segs,int sege,int qs,int qe)
{
//cout<<" q -- node = "<<node<<" segs = "<<segs<<" sege = "<<sege<<" qs = "<<qs<<" qe = "<<qe<<endl;
if(segs>sege || segs>qe || sege < qs)
{
if(tree[node].lazyset||tree[node].addval)
pushdown(node,segs,sege);
return 0;
}
if(tree[node].lazyset || tree[node].addval)
pushdown(node,segs,sege);
if(segs>=qs && sege<=qe)
{
//cout<<"q1 node = "<<node<<" segs = "<<segs<<" sege = "<<sege<<" sumsq = "<<tree[node].sumsq<<endl;
return tree[node].sum % MOD;
}
int mid= segs+sege; mid /= 2;
return (query(2*node,segs,mid,qs,qe) + query(2*node+1,mid+1,sege,qs,qe))%MOD;
}
//comm=1
void update_add(int node,int segs,int sege,int qs,int qe,int x)
{
if(segs>sege||segs>qe||sege<qs) return;
if(segs>=qs && sege<=qe)
{
tree[node].addval = (tree[node].addval+x)%MOD;
tree[node].sum = (tree[node].sum + ((LL)(sege-segs+1)*x)%MOD)%MOD;
return;
}
int mid= segs+sege; mid /= 2;
if(tree[node].lazyset || tree[node].addval)
pushdown(node,segs,sege);
update_add(2*node,segs,mid,qs,qe,x);
update_add(2*node+1,mid+1,sege,qs,qe,x);
tree[node].combine(tree[2*node],tree[2*node+1]);
}
void update_mult(int node,int segs,int sege,int qs,int qe,LL x)
{
//cout<<" ua - node = "<<node<<" segs = "<<segs<<" sege = "<<sege<<" qs = "<<qs<<" qe = "<<qe<<" x = "<<x<<endl;
if(segs>sege||segs>qe||sege<qs) return;
if(segs>=qs && sege<=qe)
{
//tree[node].addval = (tree[node].addval * x)%MOD;
tree[node].sum = (tree[node].sum * x)%MOD;
tree[node].lazyMult = 1;
tree[node].lazyVal = x;
tree[node].addval = 0;
return;
}
int mid= segs+sege; mid /= 2;
if(tree[node].lazyMult || tree[node].addval)
pushdown(node,segs,sege);
update_mult(2*node,segs,mid,qs,qe,x);
update_mult(2*node+1,mid+1,sege,qs,qe,x);
tree[node].combine(tree[2*node],tree[2*node+1]);
}
//comm=0
void update_set(int node,int segs,int sege,int qs,int qe,LL x)
{
//cout<<" node = "<<node<<" segs = "<<segs<<" sege = "<<sege<<" qs = "<<qs<<" qe = "<<qe<<" x = "<<x<<endl;
if(segs>sege||segs>qe||sege<qs)
return;
if(segs>=qs && sege<=qe)
{
tree[node].lazyset= 1;
tree[node].setval=x;
tree[node].sum = ((LL)(sege-segs+1)*x)%MOD;
tree[node].addval = 0;
return;
}
if(tree[node].lazyset || tree[node].addval)
pushdown(node,segs,sege);
int mid= segs+sege;
mid /= 2;
update_set(2*node,segs,mid,qs,qe,x);
update_set(2*node+1,mid+1,sege,qs,qe,x);
tree[node].combine(tree[2*node],tree[2*node+1]);
}
int main()
{
int test = 1;
FOR(tt,1,test+1)
{
int n,q; INT(n); INT(q);
CLR(arr);
CLR(tree);
FOR(i,0,n)
LLD(arr[i]);
build_tree(1,0,n-1);
while(q--)
{
int comm; int l,r;
INT(comm); INT(l); INT(r);
if(comm==3)
{
//set x
LL x; LLD(x);
update_set(1,0,n-1,l-1,r-1,x);
}
else if(comm==1)
{
//add x
LL x; LLD(x);
update_add(1,0,n-1,l-1,r-1,x);
}
else if(comm==2)
{
//add x
LL x; LLD(x);
update_mult(1,0,n-1,l-1,r-1,x);
}
else if(comm==4)
{
LL ans = query(1,0,n-1,l-1,r-1);
PLLD(ans);
}
}
}
return 0;
}