HDU 3308 線段樹+區間合併

/****************************************************************************************************
    尼瑪。。。一句話沒加能WA一個禮拜。。。線段樹+區間合併，主要是區間合併的細節問題。。。
****************************************************************************************************/
#include <iostream>
#include <functional>
#include <algorithm>
#include <complex>
#include <cstdlib>
#include <cstring>
#include <fstream>
#include <iomanip>
#include <sstream>
#include <utility>
#include <bitset>
#include <cctype>
#include <cstdio>
#include <limits>
#include <memory>
#include <string>
#include <vector>
#include <cmath>
#include <ctime>
#include <queue>
#include <stack>
#include <list>
#include <map>
#include <set>
using namespace std;

#define LOWBIT(x) ( (x) & ( (x) ^ ( (x) - 1 ) ) )
#define CLR(x, k) memset((x), (k), sizeof(x))
#define CPY(t, s) memcpy((t), (s), sizeof(s))
#define SC(t, s) static_cast<t>(s)
#define LEN(s) static_cast<int>( strlen((s)) )
#define SZ(s) static_cast<int>( (s).size() )

typedef double LF;
//typedef long long LL;		//GNU C++
//typedef unsigned long long ULL;
typedef __int64 LL;		//Visual C++ 2010
typedef unsigned __int64 ULL;

typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef pair<double, double> PDD;

typedef map<int, int>::iterator MI;
typedef vector<int>::iterator VI;
typedef list<int>::iterator LI;
typedef set<int>::iterator SI;

template <typename T>
T sqa(const T &x)
{
	return x * x;
}
template <typename T>
T gcd(T a, T b)
{
	if (!a || !b)
	{
		return max(a, b);
	}
	T t;
	while (t = a % b)
	{
		a = b;
		b = t;
	}
	return b;
}
template <typename T>
T ext_gcd(T a, T b, T &x, T &y)
{
	if (!b)
	{
		x = 1;
		y = 0;
		return a;
	}
	T d = ext_gcd(b, a % b, x, y);
	T t = x;					
	x = y;
	y = t - a / b * y;
	return d;
}
template <typename T>
T invmod(T a, T p)
{
	LL inv, y;
	ext_gcd(a, p, inv, y);
	inv < 0 ? inv += p : 0; 
	return inv;
}

const int INF_INT = 0x3f3f3f3f;
const LL INF_LL = 0x7fffffffffffffffLL;		//15f
const double oo = 10e9;
const double eps = 10e-7;
const double PI = acos(-1.0);

#define ONLINE_JUDGE

const int MAXN = 200004;

int test, n, m, arr[MAXN];
struct Node
{
	int left, right;
	int lmx, rmx, mmx;
	int len()
	{
		return right - left + 1;
	}
}st[MAXN << 2];

int inline ll(const int &x)
{
	return x << 1;
}
int inline rr(const int &x)
{
	return x << 1 | 1;
}
void initST()
{
	CLR(st, 0);
	return ;
}
void updateMX(int t)
{
	st[t].lmx = st[ ll(t) ].lmx;
	st[t].rmx = st[ rr(t )].rmx;
	int &mx = st[t].mmx;
	mx = 0;		//就TMD這句話沒加。。。
	if (arr[ st[ ll(t) ].right ] < arr[ st[ ll(t) ].right + 1 ])	//左右節點的銜接處，細節
	{
		if (st[ ll(t) ].len() == st[ ll(t) ].lmx)
		{
			st[t].lmx += st[ rr(t) ].lmx;
		}
		if (st[ rr(t) ].len() == st[ rr(t) ].rmx)
		{
			st[t].rmx += st[ ll(t) ].rmx;
		}
		mx = st[ ll(t) ].rmx + st[ rr(t) ].lmx;
	}
	mx = max( mx, max( st[t].lmx, st[t].rmx ) );	//顯然st[t].mmx必然是這幾個量中最大的值
	mx = max( mx, max( st[ ll(t) ].mmx, st[ rr(t) ].mmx ) );
	return ;
}
void buildST(int l, int r, int t)
{
	st[t].left = l;
	st[t].right = r;
	if (l == r)
	{
		st[t].lmx = st[t].rmx = st[t].mmx = 1;
		return ;
	}
	int mid = (l + r) >> 1;
	buildST(l, mid, ll(t));
	buildST(mid + 1, r, rr(t));
	updateMX(t);	//更新節點
	return ;
}
void updateST(int l, int r, int t)
{
	if (l <= st[t].left && st[t].right <= r)
	{
		return ;
	}
	int mid = st[ ll(t) ].right;
	if (r <= mid)
	{
		updateST(l, r, ll(t));
	}
	else if (l > mid)
	{
		updateST(l, r, rr(t));
	}
	else
	{
		updateST(l, mid, ll(t));
		updateST(mid + 1, r, rr(t));
	}
	updateMX(t);	//更新節點
	return ;
}
int queryST(int l, int r, int t)
{
	if (l <= st[t].left && st[t].right <= r)
	{
		return st[t].mmx;
	}
	int mid = st[ ll(t) ].right;
	if (r <= mid)
	{
		return queryST(l, r, ll(t));
	}
	else if (l > mid)
	{
		return queryST(l, r, rr(t));
	}
	int mx = max( queryST(l, mid, ll(t)), queryST(mid + 1, r, rr(t)) );
	if (arr[mid] < arr[mid + 1])	//這個地方有trick。。。要當心左右子節點可以銜接的情況
	{
		mx = max( mx, min( st[ ll(t) ].rmx, mid - l + 1 ) + min( st[ rr(t) ].lmx, r - mid ) );
	}
	return mx;
}
void ace()
{
	char op[2];
	int a, b;
	for (scanf("%d", &test); test--; )
	{
		scanf("%d %d", &n, &m);
		for (int i = 0; i < n; ++i)
		{
			scanf("%d", arr + i);
		}
		initST();
		buildST(0, n - 1, 1);
		while (m--)
		{
			scanf("%s %d %d", op, &a, &b);
			if ('U' == op[0])
			{
				arr[a] = b;
				updateST(a, a, 1);
			}
			else
			{
				printf("%d\n", queryST(a, b, 1));
			}
		}
	}
	return ;
}
int main()
{
#ifndef ONLINE_JUDGE
	freopen("in.txt", "r", stdin);
#endif
	ace();
	return 0;
}