hdu 2795 Billboard 线段树

#include<bits/stdc++.h>
using namespace std;

const int N= 200000+5;
int a
,ans;

struct Tree
{
int left,right;
int sum;
}tree[4*N+10];

void build(int id,int l,int r)
{
tree[id].left=l;
tree[id].right=r;
if (l==r)
tree[id].sum=a[l];
else
{
int mid=(l+r)/2;
build(id*2,l,mid);
build(id*2+1,mid+1,r);
tree[id].sum=max(tree[id*2].sum,tree[id*2+1].sum);
}
}

void update(int id,int pos,int val)
{
if (tree[id].left==tree[id].right)
tree[id].sum=tree[id].sum-val;
else
{
int mid=(tree[id].left+tree[id].right)/2;
if (pos<=mid) update(id*2,pos,val);
else update(id*2+1,pos,val);
tree[id].sum=max(tree[id*2].sum,tree[id*2+1].sum);
}
}

//查询范围内的和
int query(int id,int val)
{
int ret;
if (tree[id].left==tree[id].right)
{
tree[id].sum=tree[id].sum-val;
return tree[id].left;
}
else
{
if(tree[id*2].sum>=val) ret=query(id*2,val);
else ret=query(id*2+1,val);
}
tree[id].sum=max(tree[id*2].sum,tree[id*2+1].sum);
return ret;
}

int main()
{
int i,h,w,n,t;
while(~scanf("%d%d%d",&h,&w,&n))
{
if(h>n) h=n;
for(i=1;i<=h;i++)
a[i]=w;
build(1,1,h);
for(i=0;i<n;i++)
{
scanf("%d",&t);
if(tree[1].sum<t) printf("-1\n");
else
{
ans=query(1,t);
printf("%d\n",ans);
//printf(" %d\n",tree[ans].sum);
}
}
}
return 0;
}