CF(438D) The Child and Sequence(線段樹)

題意：對數列有三種操作：

1. Print operation l, r. Picks should write down the value of .
2. Modulo operation l, r, x. Picks should perform assignment a[i] = a[i] mod x for each i (l ≤ i ≤ r).
3. Set operation k, x. Picks should set the value of a[k] to x (in other words perform an assignment a[k] = x).

解法：線段樹更新。維護區間最大值ma和區間sum。如果訪問的x小於ma就可以忽略，否則向下更新；
代碼：

/******************************************************* author:xiefubao*******************************************************/#pragma comment(linker, "/STACK:102400000,102400000")#include <iostream>#include <cstring>#include <cstdlib>#include <cstdio>#include <queue>#include <vector>#include <algorithm>#include <cmath>#include <map>#include <set>#include <stack>#include <string.h>//freopen ("in.txt" , "r" , stdin);using namespace std;#define eps 1e-8const double pi=acos(-1.0);typedef long long LL;const int Max=100100*2;const int INF=1000000007;struct node{    int l,r;    node * left,*right;    int ma;    LL sum;} nodes[Max];int Mid(node* p){    return (p->l+p->r)/2;}int tot=0;void buildtree(node* p,int left,int right){    p->l=left;    p->r=right;    p->ma=0;    p->sum=0;    if(left==right)        return ;    int mid=(left+right)/2;    tot++;    p->left=nodes+tot;    buildtree(p->left,left,mid);    tot++;    p->right=nodes+tot;    buildtree(p->right,mid+1,right);}void update(node* p,int i,int value){    if(p->l==i&&p->r==i)    {        p->sum=value;        p->ma=value;        return ;    }    int mid=Mid(p);    if(i<=mid)        update(p->left,i,value);    else        update(p->right,i,value);    p->sum=p->left->sum+p->right->sum;    p->ma=max(p->left->ma,p->right->ma);}void update2(node* p,int l,int r,int x){    if(p->ma<x)        return;    if(p->l==l&&p->r==r&&l==r)    {        p->sum%=x;        p->ma=p->sum;        return ;    }    int mid=Mid(p);    if(r<=mid)        update2(p->left,l,r,x);    else if(l>mid)        update2(p->right,l,r,x);    else    {        update2(p->left,l,mid,x);        update2(p->right,mid+1,r,x);    }    p->sum=p->left->sum+p->right->sum;    p->ma=max(p->left->ma,p->right->ma);}LL query(node* p,int l,int r){    if(l==p->l&&r==p->r)    {        return p->sum;    }    int mid=Mid(p);    if(r<=mid)        return query(p->left,l,r);    if(l>mid)        return query(p->right,l,r);    return query(p->left,l,mid)+query(p->right,mid+1,r);;}int n,m;int main(){    while(scanf("%d%d",&n,&m)==2)    {        tot=0;        buildtree(nodes,0,n+1);        for(int i=1; i<=n; i++)        {            int a;            scanf("%d",&a);            update(nodes,i,a);        }        while(m--)        {            int t;            scanf("%d",&t);            if(t==1)            {                int l,r;                scanf("%d%d",&l,&r);                cout<<query(nodes,l,r)<<endl;            }            else if(t==2)            {                int l,r,x;                scanf("%d%d%d",&l,&r,&x);                update2(nodes,l,r,x);            }            else if(t==3)            {                int i,x;                scanf("%d%d",&i,&x);                update(nodes,i,x);            }        }    }    return 0;}