基础莫队练习

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A - D-query

#include<bits/stdc++.h>
using namespace std;
const int maxn = 3e4 + 50;
const int maxm = 2e5 + 50;
const int MAX = 1e6 + 50;
int s[maxn], ans[maxm], cnt[MAX];
int unit, num;
struct node
{
    int id, l, r;
} q[maxm];
bool cmp(node a, node b)
{
    if((a.l / unit) != (b.l / unit)) return a.l < b.l;
    return a.r < b.r;
}
void add(int x)
{
    if(++cnt[s[x]] == 1) num++;
}
void rem(int x)
{
    if(--cnt[s[x]] == 0) num--;
}
int main()
{
//    freopen("in.txt", "r", stdin);
    int n; scanf("%d", &n);
    for(int i = 1; i <= n; i++) scanf("%d", &s[i]);
    unit = sqrt(n); num = 0;
    int m; scanf("%d", &m);
    for(int i = 1; i <= m; i++)
    {
        scanf("%d%d", &q[i].l, &q[i].r);
        q[i].id = i;
    }
    sort(q + 1, q + 1 + m, cmp);
    int le = q[1].l, ri = le - 1;
    for(int i = 1; i <= m; i++)
    {
        while(le > q[i].l) add(--le);
        while(le < q[i].l) rem(le++);
        while(ri > q[i].r) rem(ri--);
        while(ri < q[i].r) add(++ri);
        ans[q[i].id] = num;
    }
    for(int i = 1; i <= m; i++) printf("%d\n", ans[i]);
    return 0;
}

B - 小Z的袜子

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 5e5 + 50;
const int maxm = 5e5 + 50;
const int MAX = 1e6 + 50;
int s[maxn], unit;
ll ans[maxm][2], num, cnt[MAX];

struct node
{
    int id, l, r;
} q[maxm];

bool cmp(node a, node b)
{
    if((a.l / unit) != (b.l / unit)) return a.l < b.l;
    return a.r < b.r;
}

void add(int x)
{
    ll y = cnt[s[x]]++;
    num = num + (y);
}
void rem(int x)
{
    ll y = --cnt[s[x]];
    num = num - (y);
}

int main()
{
//    freopen("in.txt", "r", stdin);
    int n; scanf("%d", &n);
    int m; scanf("%d", &m);
    for(int i = 1; i <= n; i++) scanf("%d", &s[i]);
    unit = sqrt(n); num = 0;
    for(int i = 1; i <= m; i++)
    {
        scanf("%d%d", &q[i].l, &q[i].r);
        q[i].id = i;
    }
    sort(q + 1, q + 1 + m, cmp);

    int le = q[1].l, ri = le - 1;
    for(int i = 1; i <= m; i++)
    {
        while(le > q[i].l) add(--le);
        while(le < q[i].l) rem(le++);
        while(ri > q[i].r) rem(ri--);
        while(ri < q[i].r) add(++ri);
        ans[q[i].id][0] = num;
        if(num == 0) ans[q[i].id][1] = 1;
        else ans[q[i].id][1] = (((ri - le + 1) * 1ll) * (ri - le)) / 2;
    }

    for(int i = 1; i <= m; i++)
    {
        ll gcd = __gcd(ans[i][0], ans[i][1]);
        printf("%lld/%lld\n", ans[i][0] / gcd, ans[i][1] / gcd);
    }

    return 0;
}

C - Powerful array

#include<bits/stdc++.h>
using namespace std;
typedef int64_t ll;
const int maxn = 2e5 + 50;
const int maxm = 2e5 + 50;
const int MAX = 1e6 + 50;
int s[maxn], unit;
ll ans[maxm], num, cnt[MAX];

struct node
{
    int id, l, r;
} q[maxm];

bool cmp(node a, node b)
{
    if((a.l / unit) != (b.l / unit)) return a.l < b.l;
    return a.r < b.r;
}

void add(int x)
{
    ll y = ++cnt[s[x]];
    num += (y*y-(y-1)*(y-1))*s[x];
}
void rem(int x)
{
    ll y = cnt[s[x]]--;
    num -= (y*y-(y-1)*(y-1))*s[x];
}

int main()
{
//    freopen("in.txt", "r", stdin);
    int n; scanf("%d", &n);
    int m; scanf("%d", &m);
    for(int i = 1; i <= n; i++) scanf("%d", &s[i]);
    unit = sqrt(n); num = 0;
    for(int i = 1; i <= m; i++)
    {
        scanf("%d%d", &q[i].l, &q[i].r);
        q[i].id = i;
    }
    sort(q + 1, q + 1 + m, cmp);

    int le = q[1].l, ri = le - 1;
    for(int i = 1; i <= m; i++)
    {
        while(le > q[i].l) add(--le);
        while(le < q[i].l) rem(le++);
        while(ri > q[i].r) rem(ri--);
        while(ri < q[i].r) add(++ri);
        ans[q[i].id] = num;
    }

    for(int i = 1; i <= m; i++) printf("%I64d\n",ans[i]);

    return 0;
}
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