hdu 1698 Just a Hook （线段树）

第一道线段树区间更新题目！

本题要求更新某一个区间的数值，最后求出所有数的总值输出！

是一道赤裸裸的线段树更新区间值得题目！

#include<stdio.h>

#define N 100100

struct node

{

int x,y,shu;

int sum;

}aa[N*3];

void CreatTree(int t,int x,int y)

{

aa[t].x=x;

aa[t].y=y;

aa[t].shu=1;

if(x==y)

{

aa[t].sum=1;

return ;

}

int temp=2*t;

int mid=(x+y)/2;

CreatTree(temp,x,mid);

CreatTree(temp+1,mid+1,y);

aa[t].sum=aa[temp].sum+aa[temp+1].sum;

}

void UpdateTree(int t,int x,int y,int shu)

{

if(x==aa[t].x&&y==aa[t].y)

{

aa[t].sum=(y-x+1)*shu;

aa[t].shu=shu;

return;

}

int mid=(aa[t].x+aa[t].y)/2;

int temp=2*t;

if(aa[t].shu!=0)

{

aa[temp].shu=aa[t].shu;

aa[temp+1].shu=aa[t].shu;

aa[temp].sum=(aa[temp].y-aa[temp].x+1)*aa[temp].shu;

aa[temp+1].sum=(aa[temp+1].y-aa[temp+1].x+1)*aa[temp+1].shu;

}

if(y<=aa[temp].y)

UpdateTree(temp,x,y,shu);

else if(x>=aa[temp+1].x)

UpdateTree(temp+1,x,y,shu);

else

{

UpdateTree(temp,x,mid,shu);

UpdateTree(temp+1,mid+1,y,shu);

}

if(aa[temp].shu==aa[temp+1].shu)

aa[t].shu=aa[temp].shu;

else

aa[t].shu=0;

aa[t].sum=aa[temp].sum+aa[temp+1].sum;

return;

}

int main()

{

int T,n,t,k,x,y,r;

r=1;

scanf("%d",&T);

while(T--)

{

scanf("%d",&n);

CreatTree(1,1,n);

scanf("%d",&t);

while(t--)

{

scanf("%d%d%d",&x,&y,&k);

UpdateTree(1,x,y,k);

}

printf("Case %d: ",r++);

printf("The total value of the hook is %d.\n",aa[1].sum);

}

return 0;

}

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1698