loj2053 「HNOI2016」大数

ref

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;
typedef long long ll;
ll p, su[100005], sv[100005], ans[100005];
int n, m, uu, vv, ww, cnt[100005], blc, bel[100005];
char ss[100005];
struct Node{
	int ll, rr, id;
}q[100005];
void qwq(){
	for(int i=1; i<=n; i++){
		su[i] = su[i-1];
		sv[i] = sv[i-1];
		if((ss[i]-'0')%p==0){
			su[i] += i;
			sv[i]++;
		}
	}
	while(m--){
		scanf("%d %d", &uu, &vv);
		printf("%lld
", su[vv]-su[uu-1]-(uu-1)*(sv[vv]-sv[uu-1]));
	}
}
bool cmp(Node x, Node y){
	if(bel[x.ll]!=bel[y.ll])	return bel[x.ll]<bel[y.ll];
	if(bel[x.ll]&1)	return x.rr<y.rr;
	else	return x.rr>y.rr;
}
void pwp(){
	ll t=1, now=0;
	blc = sqrt(n+1);
	for(int i=n; i; i--){
		su[i] = (su[i+1] + (ss[i] - '0') * t) % p;
		t = t * 10 % p;
		sv[++ww] = su[i];
		bel[i] = (i - 1) / blc + 1;
	}
	n++;
	su[n+1] = 0;
	sv[++ww] = 0;
	sort(sv+1, sv+1+ww);
	ww = unique(sv+1, sv+1+ww) - (sv + 1);
	for(int i=1; i<=n; i++)
		su[i] = lower_bound(sv+1, sv+1+ww, su[i]) - sv;
	for(int i=1; i<=m; i++){
		scanf("%d %d", &q[i].ll, &q[i].rr);
		q[i].rr++;
		q[i].id = i;
	}
	sort(q+1, q+1+m, cmp);
	int l=q[1].ll, r=l-1;
	for(int i=1; i<=m; i++){
		while(l<q[i].ll){
			cnt[su[l]]--;
			now -= cnt[su[l]];
			l++;
		}
		while(l>q[i].ll){
			l--;
			now += cnt[su[l]];
			cnt[su[l]]++;
		}
		while(r<q[i].rr){
			r++;
			now += cnt[su[r]];
			cnt[su[r]]++;
		}
		while(r>q[i].rr){
			cnt[su[r]]--;
			now -= cnt[su[r]];
			r--;
		}
		ans[q[i].id] = now;
	}
	for(int i=1; i<=m; i++)
		printf("%lld
", ans[i]);
}
int main(){
	cin>>p;
	scanf("%s", ss+1);
	n = strlen(ss+1);
	cin>>m;
	if(p==2 || p==5)	qwq();
	else	pwp();
	return 0;
}