hdu 1698 线段树成段更新

#include<iostream>
#include<cstdio>
using namespace std;

#define lson left,mid,i<<1
#define rson mid+1,right,i<<1|1

struct IntervalTree
{
    int left,right,sum,set;
}f[300005];

void pushdown(int i)
{
    if(f[i].set>0)
    {
        f[i<<1].set=f[i<<1|1].set=f[i].set;
        f[i<<1].sum=(f[i<<1].right-f[i<<1].left+1)*f[i].set;
        f[i<<1|1].sum=(f[i<<1|1].right-f[i<<1|1].left+1)*f[i].set;
        f[i].set=0;
    }
}

void pushup(int i)
{
    f[i].sum=f[i<<1].sum+f[i<<1|1].sum;
}

void bulid(int left,int right,int i)
{
    f[i].left=left,f[i].right=right,f[i].set=0;
    if(left==right)
    {
        f[i].sum=1;return ;
    }
    int mid=(left+right)>>1;
    bulid(lson);
    bulid(rson);
    pushup(i);
    return ;
}

void update(int left,int right,int set,int i)
{
    if(f[i].left==left && f[i].right==right)
    {
        f[i].set=set;
        f[i].sum=(right-left+1)*set;
        return ;
    }
    pushdown(i);
    if(f[i<<1].right>=right) update(left,right,set,i<<1);
    else if(f[i<<1|1].left<=left) update(left,right,set,i<<1|1);
    else { update(left,f[i<<1].right,set,i<<1);update(f[i<<1|1].left,right,set,i<<1|1);}
    pushup(i);
    return ;
}

int query(int left,int right,int i)
{
    if(f[i].left==left && f[i].right==right) return f[i].sum;
    pushdown(i);
    if(f[i<<1].right>=right) return query(left,right,i<<1);
    else if (f[i<<1|1].left<=left) return query(left,right,i<<1|1);
    else return query(left,f[i<<1].right,i<<1)+query(f[i<<1|1].left,right,i<<1|1);
}

int main()
{
    int icase,T,n,m,ai,bi,d;
    scanf("%d",&T);
    for(icase=1;icase<=T;icase++)
    {
        scanf("%d",&n);
        bulid(1,n,1);
        scanf("%d",&m);
        while(m--)
        {
            scanf("%d %d %d",&ai,&bi,&d);
            update(ai,bi,d,1);
        }
        printf("Case %d: The total value of the hook is %d.
",icase,f[1].sum);
    }
    return 0;
}