P1972 [SDOI2009] HH的项链
将全部输入排序,进行离散化
#include<bits/stdc++.h>
using namespace std;
#define rint register int
const int N = 1e6 + 7;
int a[N], tree[N], n, ans[N], st[N];
struct Q{
int l, r, id;
}q[N];
bool cmp(Q x, Q y){
return x.r < y.r;
}
int lowbit(int x) { return x & (- x); }
void modify(int x, int k){
for(rint i = x; i <= n;i += lowbit(i))
tree[i] += k;
}
int query(int x){
int ans = 0;
for(rint i = x; i ;i -= lowbit(i)) ans += tree[i];
return ans;
}
int main(){
int m;
scanf("%d", &n);
for(rint i = 1;i <= n;i ++) scanf("%d", &a[i]);
scanf("%d", &m);
for(rint i = 1;i <= m;i ++){
scanf("%d%d", &q[i].l, &q[i].r);
q[i].id = i;
}
int p = 1;
sort(q + 1, q + m + 1, cmp);
for(rint i = 1;i <= m;i ++){
for(rint j = p;j <= q[i].r;j ++){
if(st[a[j]]) modify(st[a[j]], -1);
modify(j, 1);
st[a[j]] = j;
}
p = q[i].r + 1;
ans[q[i].id] = query(q[i].r) - query(q[i].l - 1);
}
for(rint i = 1;i <= m;i ++){
printf("%d\n", ans[i]);
}
return 0;
}
标签:int,rint,HH,项链,SDOI2009,P1972
From: https://www.cnblogs.com/loser--QAQ/p/16904710.html