• CodeForces 438D


    At the children’s day, the child came to Picks’s house, and messed his house up. Picks was angry at him. A lot of important things were lost, in particular the favorite sequence of Picks.

    Fortunately, Picks remembers how to repair the sequence. Initially he should create an integer array a[1], a[2], …, a[n]. Then he should perform a sequence of m operations. An operation can be one of the following:

    Print operation l, r. Picks should write down the value of sum .
    Modulo operation l, r, x. Picks should perform assignment a[i] = a[i] mod x for each i (l ≤ i ≤ r).
    Set operation k, x. Picks should set the value of a[k] to x (in other words perform an assignment a[k] = x).
    Can you help Picks to perform the whole sequence of operations?

    Input

    The first line of input contains two integer: n, m (1 ≤ n, m ≤ 105). The second line contains n integers, separated by space: a[1], a[2], …, a[n] (1 ≤ a[i] ≤ 109) — initial value of array elements.

    Each of the next m lines begins with a number type .

    If type = 1, there will be two integers more in the line: l, r (1 ≤ l ≤ r ≤ n), which correspond the operation 1.
    If type = 2, there will be three integers more in the line: l, r, x (1 ≤ l ≤ r ≤ n; 1 ≤ x ≤ 109), which correspond the operation 2.
    If type = 3, there will be two integers more in the line: k, x (1 ≤ k ≤ n; 1 ≤ x ≤ 109), which correspond the operation 3.

    Output

    For each operation 1, please print a line containing the answer. Notice that the answer may exceed the 32-bit integer.

    Examples Input

    5 5
    1 2 3 4 5
    2 3 5 4
    3 3 5
    1 2 5
    2 1 3 3
    1 1 3

    Output

    8
    5

    Input

    10 10
    6 9 6 7 6 1 10 10 9 5
    1 3 9
    2 7 10 9
    2 5 10 8
    1 4 7
    3 3 7
    2 7 9 9
    1 2 4
    1 6 6
    1 5 9
    3 1 10

    Output

    49
    15
    23
    1
    9

    Note

    Consider the first testcase:

    At first, a = {1, 2, 3, 4, 5}.
    After operation 1, a = {1, 2, 3, 0, 1}.
    After operation 2, a = {1, 2, 5, 0, 1}.
    At operation 3, 2 + 5 + 0 + 1 = 8.
    After operation 4, a = {1, 2, 2, 0, 1}.
    At operation 5, 1 + 2 + 2 = 5.

    给一个序列
    支持3种操作
    1 u v 对于所有i u<=i<=v,输出a[i]的和
    2 u v t 对于所有i u<=i<=v a[i]=a[i]%t
    3 u v 表示a[u]=v(将v赋值给a[u])
    n,q<=1e5 a[i],t,v<=1e9

    Input
    5 5
    1 2 3 4 5
    2 3 5 4
    3 3 5
    1 2 5
    2 1 3 3
    1 1 3

    Output
    8
    5

    提示
    对于a%=b,如果a>=b,那么a至少除以2,也就是一个数最多减小log次

    题目大意:
    输入n和m,表示有n个数和m个询问,对于每个询问有三种操作:

    • u v 对于所有i u<=i<=v,输出a[i]的和
    • u v t 对于所有i u<=i<=v a[i]=a[i]%t
    • u v 表示a[u]=v(将v赋值给a[u])

    解题思路:
    这道题是线段树的基础题,对于这三种操作,单点替换和区间求和直接套用模板就可以,对于区间内每一个点需要剪枝,不剪枝一定会TLE,我们需要建两个树,一个存放sum的值,另一个用于存放每个节点的max,取模时我们判断一下该节点的子节点最大值是不是小于要取模的数,如果小于则直接不用判断。AC代码:

    #include <cstdio>
    #include <iostream>
    #include <algorithm>
    using namespace std;
    using ll = long long;
    const ll _max=1e5+50;
    ll arr[_max],tree[4*_max],treem[4*_max];
    int main()
    {
    	void build_tree(int,int,int);
    	void update(int,int,int,int,int);
    	ll query(int,int,int,int,int);
    	void mod1(int,int,int,int,int,int);
    	int n,m;
    	scanf("%d%d",&n,&m);
    	for ( int i = 0; i < n; i++)
    	  cin>>arr[i];
    	build_tree(0,0,n-1);
    	while(m--)
    	{
    		int k,a,b,c;
    		scanf("%d",&k);
    		if(k==1)
    		{
    			scanf("%d%d",&a,&b);
    			ll sum=query(0,0,n-1,a-1,b-1);
    			printf("%lld
    ",sum);
    		}
    		else if(k==2)
    		{
    			scanf("%d%d%d",&a,&b,&c);
    			mod1(0,0,n-1,a-1,b-1,c);
    		}
    		else
    		{
    			scanf("%d%d",&a,&b);
    			update(0,0,n-1,a-1,b);
    		}
    	}
     	//system("pause");
    	return 0;
    }
    void build_tree(int node ,int start ,int end)
    {
    	if(start==end)
    	{
    		tree[node]=arr[start];
    		treem[node]=arr[start];
    		return;
    	}
    	int left_node = node*2+1;
    	int right_node = node*2+2;
    	int mid=(start+end)>>1;
    	build_tree(left_node,start,mid);
    	build_tree(right_node,mid+1,end);
    	tree[node]=tree[left_node]+tree[right_node];
    	treem[node]=max(treem[left_node],treem[right_node]);
    }
    void update(int node, int start, int end, int idx, int val)
    {
    	if(start==end)
    	{
    		tree[node]=val;
    		treem[node]=val;
    		return;
    	}
    	int left_node = node*2+1;
    	int right_node = node*2+2;
    	int mid=(start+end)>>1;
    	if(idx>=start&&idx<=mid)
    		update(left_node,start,mid,idx,val);
    	else
    		update(right_node,mid+1,end,idx,val);
    	tree[node]=tree[left_node]+tree[right_node];
    	treem[node]=max(treem[left_node],treem[right_node]);
    }
    ll query(int node, int start, int end, int l, int r)
    {
        if(l<=start&&r>=end)
          return tree[node];   
        int left_node=node*2+1;
        int right_node=node*2+2;
        int mid=(start+end)>>1;
    	ll suml,sumr;
    	suml=sumr=0;
    	if(l<=mid)
          suml=query(left_node,start,mid,l,r);
        if(r>mid)
    	  sumr=query(right_node,mid+1,end,l,r);
        return suml+sumr;
    }
    void mod1(int node, int start, int end, int l, int r,int mod)
    {
    	if(treem[node]<mod)
    	  return;//这里注意一下,用子节点的最大值去比较
        else if(start==end)
        {
    		tree[node]=tree[node]%mod;
    		treem[node]=treem[node]%mod;
    		return;
    	}
        else 
        {
            int left_node=node*2+1;
            int right_node=node*2+2;
            int mid=(start+end)>>1;
    		if(l<=mid)
              mod1(left_node,start,mid,l,r,mod);
            if(r>mid)
    		  mod1(right_node,mid+1,end,l,r,mod);
            tree[node]=tree[left_node]+tree[right_node];
    		treem[node]=max(treem[left_node],treem[right_node]);
        }
    }
    
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  • 原文地址:https://www.cnblogs.com/Hayasaka/p/14294279.html
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