hdu 1754 I Hate It 线段树 点改动

Posted 2020-09-21 cxchanpin

// hdu 1754 I Hate It 线段树 点改动
//
// 不多说，裸的点改动
//
// 继续练
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <functional>
#include <iostream>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#define ceil(a,b) (((a)+(b)-1)/(b))
#define endl ‘\n‘
#define gcd __gcd
#define highBit(x) (1ULL<<(63-__builtin_clzll(x)))
#define popCount __builtin_popcountll
typedef long long ll;
using namespace std;
const int MOD = 1000000007;
const long double PI = acos(-1.L);

template<class T> inline T lcm(const T& a, const T& b) { return a/gcd(a, b)*b; }
template<class T> inline T lowBit(const T& x) { return x&-x; }
template<class T> inline T maximize(T& a, const T& b) { return a=a<b?b:a; }
template<class T> inline T minimize(T& a, const T& b) { return a=a<b?a:b; }

const int maxn = 8 * 1e5 +8;
int maxv[maxn];
int n,m;
const int inf = 0x7f7f7f7f;
void build(int root,int L,int R){
	if (L==R){
		scanf("%d",&maxv[root]);
		return ;
	}
	int M = L + ( R - L ) / 2;
	build(root*2,L,M);
	build(root*2+1,M+1,R);
	maxv[root] = max(maxv[root*2],maxv[root*2+1]);
}
int p,v;

void update(int root,int L,int R){
	if (L==R){
		maxv[root] = v;
		return ;
	}
	int M = L + ( R - L ) / 2;
	if (p<=M)	update(root*2,L,M);
	else update(root*2+1,M+1,R);
	maxv[root] = max(maxv[root*2],maxv[root*2+1]);
}

int query(int root,int ql,int qr,int L,int R){
	if (ql<=L && R<=qr){
		return maxv[root];
	}
	int M = L + ( R - L) / 2; 
	int ans = 0;
	if (ql<=M)	ans = max(ans,query(root*2,ql,qr,L,M));
	if (M<qr)	ans = max(ans,query(root*2+1,ql,qr,M+1,R));
	return ans;
}

void init(){
	build(1,1,n);
	char s[3];
	for (int i=0;i<m;i++){
		int x,y;
		scanf("%s%d%d",s,&x,&y);
		if (s[0]==‘Q‘){
			printf("%d\n",query(1,x,y,1,n));
		}else {
			p = x;
			v = y;
			update(1,1,n);
		}
	}
}



int main() {
//	freopen("G:\\Code\\1.txt","r",stdin);
	while(scanf("%d%d",&n,&m)!=EOF){
		init();
	}
	return 0;
}