hdu-------(1698)Just a Hook(线段树区间更新)

Just a Hook

Time Limit: 4000/2000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 17124 Accepted Submission(s): 8547


[align=left]Problem Description[/align]
In the game of DotA, Pudge’s meat hook is actually the most horrible thing for most of the heroes. The hook is made up of several consecutive metallic sticks which are of the same length.

#include<cstring>
#include<cstdio>
const int maxn=100005;
struct node
{
int lef,rig,sum;
int cnt;
int mid(){
return lef+(rig-lef>>1);
}
};

node sac[maxn*3];

void Build(int left,int right,int pos)
{
sac[pos]=(node){left,right,1};
if(left==right)return ;
int mid=sac[pos].mid();
Build(left,mid,pos<<1);
Build(mid+1,right,pos<<1|1);
sac[pos].sum=sac[pos<<1].sum+sac[pos<<1|1].sum;
}
void Update(int left,int right,int pos,int val)
{
if(left<=sac[pos].lef&&sac[pos].rig<=right){
sac[pos].sum=val*(sac[pos].rig-sac[pos].lef+1);
sac[pos].cnt=val;
return ;
}
if(sac[pos].cnt!=0){ //向下更新一次
sac[pos<<1].sum=sac[pos].cnt*(sac[pos<<1].rig-sac[pos<<1].lef+1);
sac[pos<<1|1].sum=sac[pos].cnt*(sac[pos<<1|1].rig-sac[pos<<1|1].lef+1);
sac[pos<<1|1].cnt=sac[pos<<1].cnt=sac[pos].cnt;
sac[pos].cnt=0;
}
int mid=sac[pos].mid();
if(mid>=left)
Update(left,right,pos<<1,val);
if(mid<right)
Update(left,right,pos<<1|1,val);
sac[pos].sum=sac[pos<<1].sum+sac[pos<<1|1].sum;
}
int main()
{
int test,n,Q;
int a,b,c;
scanf("%d",&test);
for(int i=1;i<=test;i++){
scanf("%d%d",&n,&Q);
Build(1,n,1);
while(Q--)
{
scanf("%d%d%d",&a,&b,&c);
Update(a,b,1,c);
}
printf("Case %d: The total value of the hook is %d.\n",i,sac[1].sum);
}
}

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