51nod 1290 Counting Diff Pairs 莫队 + bit

  1                                             
  2   //File Name: nod1290.cpp
  3   //Author: long
  4   //Mail: 736726758@qq.com
  5   //Created Time: 2016年09月16日 星期五 17时22分07秒
  6                                    
  7 #include <stdio.h>
  8 #include <string.h>
  9 #include <iostream>
 10 #include <algorithm>
 11 #include <math.h>
 12 #define LL long long
 13 #define hash _hash_
 14 using namespace std;
 15 const int MAXN = 50010;
 16 int hash[MAXN * 3],num[MAXN * 3],top,tot;
 17 void hash_init(){
 18     sort(num+1,num+top+1);
 19     tot = 0;
 20     hash[++tot] = num[1];
 21     for(int i=2;i<=top;i++)
 22         if(num[i] != num[i-1])
 23             hash[++tot] = num[i];
 24 }
 25 int hash_find(int x){
 26     int l = 1,r = tot,m;    
 27     while(l <= r){
 28         m = l + r >> 1;
 29         if(hash[m] < x) l = m + 1;
 30         else r = m - 1;
 31     }    
 32     return l;
 33 }
 34 int a[MAXN],b[MAXN],c[MAXN],bel[MAXN],bit[MAXN * 3],cur_l,cur_r,K;
 35 LL ans[MAXN],cur_ans;
 36 struct Query{
 37     int ql,qr,id;
 38 }que[MAXN];
 39 bool cmp(Query x,Query y){
 40     if(bel[x.ql] == bel[y.ql]) return x.qr < y.qr;
 41     return bel[x.ql] < bel[y.ql];
 42 }
 43 void update(int x,int add){
 44     for(int i=x;i<=tot;i+=i&-i)
 45         bit[i] += add;
 46 }
 47 int query(int x){
 48     int res = 0;
 49     for(int i=x;i>0;i-=i&-i)
 50         res += bit[i];
 51     return res;
 52 }
 53 int cal(int u){
 54     return query(c[u]) - query(b[u] - 1);
 55 }
 56 void update_l(int to_l){
 57     while(cur_l < to_l){
 58         update(a[cur_l],-1);
 59         cur_ans -= cal(cur_l);
 60         cur_l++;
 61     }
 62     while(cur_l > to_l){
 63         cur_l--;
 64         cur_ans += cal(cur_l);
 65         update(a[cur_l],1);
 66     }
 67 }
 68 void update_r(int to_r){
 69     while(cur_r < to_r){
 70         cur_r++;
 71         cur_ans += cal(cur_r);
 72         update(a[cur_r],1);
 73     }
 74     while(cur_r > to_r){
 75         update(a[cur_r],-1);
 76         cur_ans -= cal(cur_r);
 77         cur_r--;
 78     }
 79 }
 80 void solve(int n,int q){
 81     hash_init();
 82     for(int i=1;i<=n;i++){
 83         b[i] = hash_find(a[i] - K);
 84         c[i] = hash_find(a[i] + K);
 85         a[i] = hash_find(a[i]);
 86     }
 87     memset(ans,0,sizeof ans);
 88     int NUM = (int)sqrt(n + 0.5);
 89     for(int i=1;i<=n;i++) 
 90         bel[i] = (i - 1) / NUM;
 91     sort(que+1,que+q+1,cmp);
 92     memset(bit,0,sizeof bit);
 93     update(a[1],1);
 94     cur_l = cur_r = 1;
 95     cur_ans = 0;
 96     for(int i=1;i<=q;i++){
 97         update_r(que[i].qr);
 98         update_l(que[i].ql);
 99         ans[que[i].id] = cur_ans;
100     }
101 }
102 int main(){
103     int n,q;
104     while(~scanf("%d %d %d",&n,&K,&q)){
105         top = 0;
106         for(int i=1;i<=n;i++){
107             scanf("%d",a + i);
108             num[++top] = a[i];
109             num[++top] = a[i] - K;
110             num[++top] = a[i] + K;
111         }
112         for(int i=1;i<=q;i++){
113             scanf("%d %d",&que[i].ql,&que[i].qr);
114             que[i].ql++,que[i].qr++,que[i].id = i;
115         }
116         solve(n,q);
117         for(int i=1;i<=q;i++)
118             printf("%lld\n",ans[i]);
119     }
120     return 0;
121 }