\(\text{Solution}\)

\(\text{code}\)

#include 
#include 
#include 
#define IN inline
#define RE register
using namespace std;
typedef long long LL;

const int N = 1e6 + 5;
int n, q;
LL tag[N];

struct BIT{
	LL c[N];
	IN int lowbit(int x){return x & (-x);}
	IN void add(int x, LL v){for(; x <= n; x += lowbit(x)) c[x] += v;}
	IN LL Query(int x){LL s = 0; for(; x; x -= lowbit(x)) s += c[x]; return s;}
}T;

struct node{
	int l, r; mutable int v;
	IN node(int l, int r, int v):l(l), r(r), v(v){};
	IN bool operator < (const node &a) const {return l < a.l;}
};
set odt;
typedef set::iterator IT;

IN IT split(int x)
{
	if (x > n) return odt.end();
	IT it = --odt.upper_bound(node{x, 0, 0});
	if (it->l == x) return it;
	int l = it->l, r = it->r, v = it->v;
	odt.erase(it), odt.insert(node{l, x - 1, v});
	return odt.insert(node{x, r, v}).first;
}
IN void assign(int l, int r, int c)
{
	IT itr = split(r + 1), itl = split(l);
	for(RE IT it = itl; it != itr; it++)
		T.add(it->l, tag[it->v]), T.add(it->r + 1, -tag[it->v]);
	odt.erase(itl, itr), odt.insert(node{l, r, c});
	T.add(l, -tag[c]), T.add(r + 1, tag[c]);
}
IN int find(int x)
{
	IT it = odt.lower_bound(node{x, 0, 0});
	if (it->l == x) return it->v;
	return (--it)->v;
}

IN void read(int &x)
{
	x = 0; int f = 1; char ch = getchar();
	for(; !isdigit(ch); f = (ch == '-' ? -1 : 1), ch = getchar()); 
	for(; isdigit(ch); x = (x<<3)+(x<<1)+(ch^48), ch = getchar());
	x *= f;
}

int main()
{
	read(n), read(q), odt.insert(node{1, n, 1});
	char op[10];
	for(RE int l, r, c, x; q; --q)
	{
		scanf("%s", op);
		if (op[0] == 'C') read(l), read(r), read(c), assign(l, r, c);
		else if (op[0] == 'A') read(c), read(x), tag[c] += x;
		else read(x), printf("%lld\n", T.Query(x) + tag[find(x)]);
	}
}