704A - Thor - CodeForces Solution

#include<cstdio>
int h,t,z,x,Q,r,q[300001],c[300001],Rc[300001];
int main()
{
	for(scanf("%d%d",&x,&Q);Q--;printf("%d\n",r))
	{
		scanf("%d%d",&z,&x);
		if(z==1)++r,q[++t]=x,++c[x],++Rc[x];else
		if(z==2)r-=Rc[x],Rc[x]=0;else
		for(;h<x;)if(--c[z=q[++h]],Rc[z]>c[z])--r,--Rc[z];
	}
}