• codeforces


    C. DZY Loves Colors
    time limit per test
    2 seconds
    memory limit per test
    256 megabytes
    input
    standard input
    output
    standard output

    DZY loves colors, and he enjoys painting.

    On a colorful day, DZY gets a colorful ribbon, which consists of n units (they are numbered from 1 to n from left to right). The color of the i-th unit of the ribbon is i at first. It is colorful enough, but we still consider that the colorfulness of each unit is 0 at first.

    DZY loves painting, we know. He takes up a paintbrush with color x and uses it to draw a line on the ribbon. In such a case some contiguous units are painted. Imagine that the color of unit i currently is y. When it is painted by this paintbrush, the color of the unit becomes x, and the colorfulness of the unit increases by |x - y|.

    DZY wants to perform m operations, each operation can be one of the following:

    1. Paint all the units with numbers between l and r (both inclusive) with color x.
    2. Ask the sum of colorfulness of the units between l and r (both inclusive).

    Can you help DZY?

    Input

    The first line contains two space-separated integers n, m (1 ≤ n, m ≤ 105).

    Each of the next m lines begins with a integer type (1 ≤ type ≤ 2), which represents the type of this operation.

    If type = 1, there will be 3 more integers l, r, x (1 ≤ l ≤ r ≤ n; 1 ≤ x ≤ 108) in this line, describing an operation 1.

    If type = 2, there will be 2 more integers l, r (1 ≤ l ≤ r ≤ n) in this line, describing an operation 2.

    Output

    For each operation 2, print a line containing the answer — sum of colorfulness.

    Examples
    input
    Copy
    3 3
    1 1 2 4
    1 2 3 5
    2 1 3
    output
    Copy
    8
    input
    Copy
    3 4
    1 1 3 4
    2 1 1
    2 2 2
    2 3 3
    output
    Copy
    3
    2
    1
    input
    Copy
    10 6
    1 1 5 3
    1 2 7 9
    1 10 10 11
    1 3 8 12
    1 1 10 3
    2 1 10
    output
    Copy
    129
    Note

    In the first sample, the color of each unit is initially [1, 2, 3], and the colorfulness is [0, 0, 0].

    After the first operation, colors become [4, 4, 3], colorfulness become [3, 2, 0].

    After the second operation, colors become [4, 5, 5], colorfulness become [3, 3, 2].

    So the answer to the only operation of type 2 is 8.

    题目意思:给出一个序列初始值为1~n,我们能对它有两种操作,1.l~r区间颜色染成x 然后我们能得到 abs(x-col[l])的色差 2.求l~r色差和

    思路:线段树的区间更新,我们维护一个颜色,如果颜色相同时才能成段更新

    #include <bits/stdc++.h>
    #define ll long long
    #define lson l,m,rt<<1
    #define rson m+1,r,rt<<1|1
    using namespace std;
    const int maxn = 100005;
    ll col[maxn<<2],lazy[maxn<<2],sum[maxn<<2];
    void push_up(int rt)
    {
        sum[rt]=sum[rt<<1]+sum[rt<<1|1];
        col[rt]=(col[rt<<1]==col[rt<<1|1]?col[rt<<1]:0);
    }
    void build(int l,int r,int rt)
    {
        if(l==r)
        {
            col[rt]=l;
            return ;
        }
        int m=(l+r)>>1;
        build(lson);
        build(rson);
        push_up(rt);
    }
    void push_down(int rt,int len)
    {
        if(col[rt])
        {
            col[rt<<1]=col[rt<<1|1]=col[rt];
            sum[rt<<1]+=lazy[rt]*(ll)(len-(len>>1));
            sum[rt<<1|1]+=lazy[rt]*(ll)(len>>1);
            lazy[rt<<1]+=lazy[rt];
            lazy[rt<<1|1]+=lazy[rt];
            col[rt]=lazy[rt]=0;
        }
    }
    void updata(int l,int r,int rt,int L,int R,ll val)
    {
        if(L<=l&&r<=R&&col[rt])
        {
            sum[rt]+=abs(col[rt]-val)*(ll)(r-l+1);
            lazy[rt]+=abs(col[rt]-val);
            col[rt]=val;
            return ;
        }
        push_down(rt,r-l+1);
        int m=(l+r)>>1;
        if(L<=m) updata(lson,L,R,val);
        if(R>m) updata(rson,L,R,val);
        push_up(rt);
    }
    ll query(int l,int r,int rt,int L,int R)
    {
        if(L<=l&&r<=R)
        {
            return sum[rt];
        }
        push_down(rt,r-l+1);
        ll ans=0;
        int m=(l+r)>>1;
        if(L<=m) ans+=query(lson,L,R);
        if(R>m) ans+=query(rson,L,R);
        return ans;
    }
    int main()
    {
        int n,m,fg,l,r;
        ll x;
        scanf("%d %d",&n,&m);
        build(1,n,1);
        while(m--)
        {
            scanf("%d",&fg);
            if(fg==1)
            {
                scanf("%d %d %lld",&l,&r,&x);
                updata(1,n,1,l,r,x);
            }
            else
            {
                scanf("%d %d",&l,&r);
                printf("%lld
    ",query(1,n,1,l,r));
            }
        }
    }
    View Code
    PS:摸鱼怪的博客分享,欢迎感谢各路大牛的指点~
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  • 原文地址:https://www.cnblogs.com/MengX/p/9451934.html
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