【HDU】1698 Just a Hook

#include<cstdio>
#include<cstring>
#define MAXN 100010
int tree[MAXN<<2],lazy[MAXN<<2];
inline void PushUp(int rt)
{
    tree[rt]=tree[rt<<1]+tree[rt<<1|1];
}
void Build(int L,int R,int rt)
{
    lazy[rt]=0;
    if(L==R)
        tree[rt]=1;
    else
    {
        int mid=(L+R)>>1;
        Build(L,mid,rt<<1);
        Build(mid+1,R,rt<<1|1);
        PushUp(rt);
    }
}
inline void PushDown(int mid,int L,int R,int rt)
{
    lazy[rt<<1]=lazy[rt<<1|1]=lazy[rt];
    tree[rt<<1]=(mid-L+1)*lazy[rt];
    tree[rt<<1|1]=(R-mid)*lazy[rt];
    lazy[rt]=0;
}
void Update(int x,int y,int z,int L,int R,int rt)
{
    if(x<=L&&R<=y)
    {
        lazy[rt]=z;
        tree[rt]=(R-L+1)*z;
    }
    else
    {
        int mid=(L+R)>>1;
        if(lazy[rt])
            PushDown(mid,L,R,rt);
        if(mid>=x)
            Update(x,y,z,L,mid,rt<<1);
        if(y>mid)
            Update(x,y,z,mid+1,R,rt<<1|1);
        PushUp(rt);
    }
}
int main()
{
    int c,n,q,x,y,z,ca=1;
    scanf("%d",&c);
    while(c--)
    {
        scanf("%d%d",&n,&q);
        Build(1,n,1);
        while(q--)
        {
            scanf("%d%d%d",&x,&y,&z);
            Update(x,y,z,1,n,1);
        }
        printf("Case %d: The total value of the hook is %d.\n",ca++,tree[1]);
    }
    return 0;
}