codeforces F. Machine Learning

题目:http://codeforces.com/contest/940/problem/F

题意:给一个长度为n的序列和q次操作。

操作1:查询l,r区间内所有数字出现次数所组成的数组中没有出现过的最小正整数。

操作2:将a[p]修改为y。

带修改的莫队算法,每次答案暴力得出。

#include
#include
#include
#include
#include
using namespace std;
const int maxm = 100005;
int a[maxm], s[maxm * 2], ss[maxm * 2], now[maxm], b[maxm], ans[maxm];
struct Up
{
	int x, v, lv;
}c[maxm];
struct node
{
	int id, l, r, t;
	bool operator < (const node &A) const
	{
		if (b[l] == b[A.l])
			return b[r] == b[A.r] ? tvis;
void update(int v, int val)
{
	int &x = s[v];
	if (x > 0) ss[x]--;
	x += val;
	if (x > 0) ss[x]++;
}
void change(int k, int v, int l, int r)
{
	if (k >= l&&k <= r)
	{
		update(a[k], -1);
		update(v, 1);
	}
	a[k] = v;
}
int main()
{
	int n, i, j, k, m, sc, sp, cnt, d, x, y, block;
	scanf("%d%d", &n, &m);
	sc = 0, sp = 0, cnt = 0;
	block = 2000;
	for (i = 1;i <= n;i++)
	{
		scanf("%d", &a[i]);
		int &t = vis[a[i]];
		if (!t) t = ++cnt;
		now[i] = a[i] = t;
		b[i] = i / block + 1;
	}
	for (i = 1;i <= m;i++)
	{
		scanf("%d%d%d", &d, &x, &y);
		if (d == 1)
		{
			p[++sp].l = x, p[sp].r = y;
			p[sp].t = sc, p[sp].id = sp;
		}
		else
		{
			int &t = vis[y];
			if (!t) t = ++cnt;
			y = t;
			c[++sc].x = x, c[sc].v = y;
			c[sc].lv = now[x], now[x] = y;
		}
	}
	sort(p + 1, p + 1 + sp);
	int l = 1, r = 0, time = 0;
	for (i = 1;i <= sp;i++)
	{
		while (time < p[i].t)
			change(c[time + 1].x, c[time + 1].v, l, r), time++;
		while (time > p[i].t)
			change(c[time].x, c[time].lv, l, r), time--;
		while (r < p[i].r) update(a[++r], 1);
		while (r > p[i].r) update(a[r--], -1);
		while (l < p[i].l) update(a[l++], -1);
		while (l > p[i].l) update(a[--l], 1);
		int rev = 1;
		while (ss[rev] > 0) rev++;
		ans[p[i].id] = rev;
	}
	for (i = 1;i <= sp;i++)
		printf("%d\n", ans[i]);
	return 0;
}

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