hdu 1698 Just a Hook(线段树求总区间和)

#include <stdio.h>
struct Seg_tree
{
int left,right;
int val,sum;
Seg_tree(){val = 0;}
}tree[400010];
void CreateTree(int locate,int left,int right)
{
tree[locate].left = left;
tree[locate].right = right;
if(locate==1)tree[locate].val = 1;
tree[locate].sum = right-left+1;
if(left == right)
return;
int mid = (left+right)>>1;
CreateTree(2*locate,left,mid);
CreateTree(2*locate+1,mid+1,right);
}
/*更新区间值*/
void update(int locate,int left,int right,int val)
{
if (tree[locate].right==right&&tree[locate].left==left)
{
tree[locate].val = val;
tree[locate].sum = val*(tree[locate].right-tree[locate].left+1);
return;
}
if (tree[locate].val>0)
{
tree[2*locate].val = tree[locate].val;
tree[2*locate].sum = (tree[2*locate].right-tree[2*locate].left+1)*tree[locate].val;
tree[2*locate+1].val = tree[locate].val;
tree[2*locate+1].sum = (tree[2*locate+1].right-tree[2*locate+1].left+1)*tree[locate].val;
tree[locate].val = tree[locate].sum = 0;
}
int mid = (tree[locate].right+tree[locate].left)>>1;
if (right<=mid)
update(2*locate,left,right,val);
else if(left>mid)
update(2*locate+1,left,right,val);
else
{
update(2*locate,left,mid,val);
update(2*locate+1,mid+1,right,val);
}

tree[locate].sum = tree[locate*2].sum+tree[2*locate+1].sum;
}
int main()
{
int test,n,q,a,b,c,i = 1;
scanf("%d",&test);
while (test--)
{
scanf("%d",&n);
CreateTree(1,1,n);
scanf("%d",&q);
while (q--)
{
scanf("%d%d%d",&a,&b,&c);
update(1,a,b,c);
}
printf("Case %d: The total value of the hook is %d./n",i++,tree[1].sum);
}
return 0;