P4879 ycz的妹子

思路

让你干啥你就干啥呗
查询第x个妹子就get一下再修改
这里稳一点就维护了三个东西，也许两个也可以

代码

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#define ls rt<<1
#define rs rt<<1|1
#define ll long long
#define FOR(i,a,b) for(int i=a;i<=b;++i)
using namespace std;
const int maxn = 5e5 + 7;
int read() {
    int x = 0, f = 1; char s = getchar();
    for (; s < '0' || s > '9'; s = getchar()) if (s == '-') f = -1;
    for (; s >= '0' && s <= '9'; s = getchar()) x = x * 10 + s - '0';
    return x * f;
}
int n,m;
int a[maxn];
struct node {
	int l,r,size,gs;
	ll sum,ans;
}e[maxn<<2];
void pushup(int rt) {
	e[rt].gs=e[ls].gs+e[rs].gs;
	e[rt].ans=e[ls].ans+e[rs].ans;
	e[rt].sum=e[ls].sum+e[rs].sum;
}
void build(int l,int r,int rt) {
	e[rt].l=l,e[rt].r=r,e[rt].size=r-l+1;
	if(l==r) {
		if(l<=n) {
			e[rt].gs=1;
			e[rt].ans=e[rt].sum=a[l];
		}
		return;
	}
	int mid=(l+r)>>1;
	build(l,mid,ls);
	build(mid+1,r,rs);
	pushup(rt);
}
void modify_1(int L,int k,int rt) { // The Lth city plus k .
	if(e[rt].l==e[rt].r) {
		e[rt].sum+=k;
		if(e[rt].gs) e[rt].ans+=k;
		return;
	}
	int mid=(e[rt].l+e[rt].r)>>1;
	if(L<=mid) modify_1(L,k,ls);
	else modify_1(L,k,rs);
	pushup(rt);
}
void modify_2(int L,int k,int rt) { // The Lth sister fell in love with him.
	if(e[rt].l==e[rt].r) {
	    e[rt].gs=k;
		e[rt].ans=e[rt].sum=0;
		return;
	}
	int mid=(e[rt].l+e[rt].r)>>1;
	if(L<=mid) modify_2(L,k,ls);
	else modify_2(L,k,rs);
	pushup(rt);	
}
int get(int k,int rt) {
	if(e[rt].l==e[rt].r)
		return e[rt].l;
	if(k <= e[ls].gs) return get(k,ls);
	else return get(k-e[ls].gs,rs);
}
int main() {
	n=read(),m=read();
	FOR(i,1,n) a[i]=read();
	build(1,5e5,1);
	FOR(i,1,m) {
		char s;
		scanf("%s",&s);
		if(s=='Q') {
			printf("%lld
",e[1].ans);
		} else if(s=='C') {
			int x=read(),y=read();
			modify_1(x,-y,1);
		} else if(s=='D') {
			int x=read();
			modify_2(get(x,1),0,1);
		} else if(s=='I') {
			int x=read(),y=read();
			modify_2(x,1,1);
			modify_1(x,y,1);
		}
	}
	return 0;
}