hdu-2795

  • 题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=2795

  • 题目大意: 给你一个HW的黑板,在上面贴海报,但是有一个要求,每次只能贴最上面的且靠右的地方,每张海报都是1W的,不能覆盖,问每张海报贴在第几行

  • 思路:线段树询问区间最大值,因为N只有200000, 所以按照H来建树

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using namespace std;
const int kMaxN = 200001;
int kMax[kMaxN<<2];
int kN, kW, kH;
void (int rt)
{
kMax[rt] = max(kMax[rt<<1], kMax[rt<<1|1]);
}
void BuildTree(int l, int r, int rt)
{
if(l == r){
kMax[rt] = kW;
return;
}
int mid = (l + r) >> 1;
BuildTree(l, mid, rt<<1);
BuildTree(mid+1, r, rt<<1|1);
PushUp(rt);
}
int QueryTree(int w, int l, int r, int rt)
{
if(kMax[rt] < w)
return -1;
if(l == r)
{
kMax[rt] -= w;
return l;
}
int mid = (l + r) >> 1;
int ret = kMaxN;
if(kMax[rt<<1] >= w)
ret = min(ret, QueryTree(w, l, (l+r)>>1, rt<<1));
else
ret = min(ret, QueryTree(w, mid + 1, r, rt<<1|1));
PushUp(rt);
return ret;
}
int main()
{
while(scanf("%d %d %d", &kH,&kW, &kN)!=EOF)
{
kH = min(kN, kH);
BuildTree(1, kH, 1);
int w;
for(int i = 0; i < kN; ++i)
{
scanf("%d", &w);
printf("%dn", QueryTree(w, 1, kH, 1));
}
}
return 0;
}