HDU 4417 Super Mario(划分树+二分)

题目链接

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define N 100100
struct node
{
    int l,r;
}tree[4*N];
int sorted[N];
int lnum[20][N];
int val[20][N];
void build(int d,int l,int r,int rt)
{
    int m,lsame,i,lpos,rpos,same;
    tree[rt].l = l;
    tree[rt].r = r;
    if(l == r) return ;
    m = (l+r)>>1;
    lsame = (m - l + 1);
    for(i = l;i <= r;i ++)
    {
        if(val[d][i] < sorted[m])
        lsame --;
    }
    lpos = l;
    rpos = m+1;
    same = 0;
    for(i = l;i <= r;i ++)
    {
        if(i == l)
        lnum[d][i] = 0;
        else
        lnum[d][i] = lnum[d][i-1];
        if(val[d][i] < sorted[m])
        {
            lnum[d][i] ++;
            val[d+1][lpos++] = val[d][i];
        }
        else if(val[d][i] > sorted[m])
        {
            val[d+1][rpos++] = val[d][i];
        }
        else
        {
            if(same < lsame)
            {
                same ++;
                lnum[d][i] ++;
                val[d+1][lpos++] = val[d][i];
            }
            else
            {
                val[d+1][rpos++] = val[d][i];
            }
        }
    }
    build(d+1,lson);
    build(d+1,rson);
}
int query(int d,int k,int l,int r,int rt)
{
    int s,ss,nl,nr,m,rs,rss;
    if(l == r)
    {
        return val[d][l];
    }
    if(l == tree[rt].l)
    {
        s = lnum[d][r];
        ss = 0;
    }
    else
    {
        s = lnum[d][r] - lnum[d][l-1];
        ss = lnum[d][l-1];
    }
    if(s >= k)
    {
        nl = ss + tree[rt].l;
        nr = ss + tree[rt].l + s - 1;
        return query(d+1,k,nl,nr,rt<<1);
    }
    else
    {
        m = (tree[rt].l + tree[rt].r)>>1;
        rss = l - tree[rt].l - ss;
        rs = r - l + 1 - s;
        nl = m + rss + 1;
        nr = m + rs + rss;
        return query(d+1,k-s,nl,nr,rt<<1|1);
    }
}
int bin(int l,int r,int key)
{
    int str,end,mid,temp;
    str = 1;end = r-l+1;
    while(str < end)
    {
        mid = (str + end + 1)/2;
        temp = query(0,mid,l,r,1);
        if(temp > key)
        end = mid - 1;
        else
        str = mid;
    }
    return end;
}
int main()
{
    int i,n,m,x,y,k,t,cas = 1;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        for(i = 1;i <= n;i ++)
        {
            scanf("%d",&val[0][i]);
            sorted[i] = val[0][i];
        }
        sort(sorted+1,sorted+n+1);
        build(0,1,n,1);
        printf("Case %d:
",cas++);
        for(i = 0;i < m;i ++)
        {
            scanf("%d%d%d",&x,&y,&k);
            x ++;
            y ++;
            if(k > query(0,y-x+1,x,y,1))
            printf("%d
",y-x+1);
            else if(k < query(0,1,x,y,1))
            printf("0
");
            else
            printf("%d
",bin(x,y,k));
        }
    }
    return 0;
}