Codeforces 444 C. dzy loves colors (line segment tree)

Question:

1 l r x operation description [L, R] nodes are painted in X color, and the value of each node is added | Y-x | Y is the color before painting.

2 L r operation, find the sum on [L, R.

Train of Thought Analysis:

Assume that an interval is of the same color. Then we can merge the operations.

So we can look for the same range before.

However, the question is how to merge operations.

Then we define a Val to indicate the value that should be added to each position in this range.

This value can be added during Pushdown.

#include <cstdio>#include <iostream>#include <cstring>#include <algorithm>#define maxn 100005#define lson num<<1,s,mid#define rson num<<1|1,mid+1,eusing namespace std;typedef long long LL;LL color[maxn<<2];LL sum[maxn<<2];LL val[maxn<<2];LL Abs(LL x){    return x>0?x:-x;}void pushdown(int num,int s,int e){    if(color[num]!=-1)    {        int mid=(s+e)>>1;        sum[num<<1]+=val[num]*(mid-s+1);        sum[num<<1|1]+=val[num]*(e-mid);        val[num<<1]+=val[num];        val[num<<1|1]+=val[num];        color[num<<1]=color[num<<1|1]=color[num];        color[num]=-1;        val[num]=0;    }}void pushup(int num){    if(color[num<<1]==color[num<<1|1])        color[num]=color[num<<1];    else color[num]=-1;    sum[num]=sum[num<<1]+sum[num<<1|1];}void build(int num,int s,int e){    sum[num]=0;    val[num]=0;    color[num]=-1;    if(s==e)    {        color[num]=s;        return;    }    int mid=(s+e)>>1;    build(lson);    build(rson);}void update(int num,int s,int e,int l,int r,LL v){    if(l<=s && r>=e)    {        if(color[num]!=-1)        {            sum[num]+=(LL)Abs(v-color[num])*(e-s+1);            val[num]+=Abs(color[num]-v);            color[num]=v;            return;        }    }    int mid=(s+e)>>1;    pushdown(num,s,e);    if(l<=mid)update(lson,l,r,v);    if(r>mid)update(rson,l,r,v);    pushup(num);}LL query(int num,int s,int e,int l,int r){    if(l<=s && r>=e)    {        return sum[num];    }    int mid=(s+e)>>1;    pushdown(num,s,e);    if(r<=mid)return query(lson,l,r);    else if(l>mid)return query(rson,l,r);    else return query(lson,l,mid)+query(rson,mid+1,r);}int main(){    int n,m;    scanf("%d%d",&n,&m);    build(1,1,n);    while(m--)    {        int type;        scanf("%d",&type);        if(type==1){            int l,r;            LL x;            scanf("%d%d%I64d",&l,&r,&x);            update(1,1,n,l,r,x);        }        else        {            int l,r;            scanf("%d%d",&l,&r);            printf("%I64d\n",query(1,1,n,l,r));        }    }    return 0;}/*10 101 5 9 62 6 101 1 9 31 3 10 52 4 6*/

Codeforces 444 C. dzy loves colors (line segment tree)