HDU 4417 劃分樹+二分

#include<iostream>#include<algorithm>#include<cmath>#include<cstdio>using namespace std;#define manx 100009int x[manx],tree[20][manx],sum_left[20][manx];void make(int level,int left,int right){    if(left==right) return ;     int mid = (left+right)>>1;    int num = mid - left + 1;    for(int i=left;i<=right;i++){        if(tree[level][i]<x[mid])        num--;    }    int lpos = left, rpos = mid+1;    for(int i=left; i<=right; i++){        if(i==left) sum_left[level][i]=0;        else sum_left[level][i]=sum_left[level][i-1];        if(tree[level][i]<x[mid]){            sum_left[level][i]++;            tree[level+1][lpos++] = tree[level][i];            }        else if(tree[level][i]>x[mid])            tree[level+1][rpos++] = tree[level][i];        else {            if(num > 0){                num--;                sum_left[level][i]++;                tree[level+1][lpos++]=tree[level][i];            }            else tree[level+1][rpos++]=tree[level][i];         }    }    make(level+1,left,mid);    make(level+1,mid+1,right);}int query(int level,int left,int right,int l,int r,int k){    if(l==r) return tree[level][l];    int s, ss, mid = (left+right)>>1;    if(left==l){        s = 0;        ss = sum_left[level][r];    }    else {        s = sum_left[level][l-1];        ss = sum_left[level][r]-s;    }    int newl,newr;    if(k<=ss){        newl = left + s;        newr = left + s + ss - 1;        return query(level+1,left,mid,newl,newr,k);    }    else {        newl = mid + (l-left-s+1);        newr = mid + (r-left-s-ss+1);        return query(level+1,mid+1,right,newl,newr,k-ss);    }} int main(){    int n,q,ca=0;    int t;    scanf("%d",&t);    while(t--){    scanf("%d%d",&n,&q);        for(int i=1;i<=n;i++){            scanf("%d",&tree[0][i]);            x[i] = tree[0][i];        }        sort(x+1,x+n+1);        make(0,1,n);        printf("Case %d:\n",++ca);        while(q--){            int l,r,k;            scanf("%d%d%d",&l,&r,&k);            l++, r++;            int mid,left=1,right=r-l+1,ans=0;;            while(left<=right){                mid = (left+right)>>1;                if(query(0,1,n,l,r,mid)>k) right=mid-1;                else {                    ans = mid;                     left = mid+1;                }            }                           printf("%d\n",ans);        }    }}