I Hate It HDU-1754 线段树

I Hate It

code

/*Siberian Squirrel*/
/*Cute KiloFish*/
#include<bits/stdc++.h>

#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define ACM_LOCAL

using namespace std;
typedef long long ll;

const double PI = acos(-1);
const double eps = 1e-4;
/*const int MOD = 998244353, r = 119, k = 23, g = 3;
const int MOD = 1004535809, r = 479, k = 21, g = 3;*/
const int MOD = 1e9 + 7;
const int M = 1e7 + 10;
const int N = 3e5 + 10;

//inline int rnd(){static int seed=2333;return seed=(((seed*666666ll+20050818)%998244353)^1000000007)%1004535809;}

int n, m, a[N];
struct node {
    
    
    int l, r;
    int maxx;
}seg[N << 2];

void pushup(int rt) {
    
    
    seg[rt].maxx = max(seg[rt << 1].maxx, seg[rt << 1 | 1].maxx);
}

void build(int rt, int l, int r) {
    
    
    seg[rt] = {
    
    l, r, 0};
    if(l == r) {
    
    
        seg[rt].maxx = max(seg[rt].maxx, a[l]);
        return ;
    }
    int mid = l + r >> 1;
    build(rt << 1, l, mid);
    build(rt << 1 | 1, mid + 1, r);
    pushup(rt);
}

void modify(int rt, int l, int r, int x) {
    
    
    if(l <= seg[rt].l && seg[rt].r <= r) {
    
    
        seg[rt].maxx = max(seg[rt].maxx, x);
        return;
    }
    int mid = seg[rt].l + seg[rt].r >> 1;
    if(l <= mid) modify(rt << 1, l, r, x);
    if(mid < r) modify(rt << 1 | 1, l, r, x);
    pushup(rt);
}

int query(int rt, int l, int r) {
    
    
    if(l <= seg[rt].l && seg[rt].r <= r) {
    
    
        return seg[rt].maxx;
    }
    int mid = seg[rt].l + seg[rt].r >> 1;
    int maxx = 0;
    if(l <= mid) maxx = max(maxx, query(rt << 1, l, r));
    if(mid < r) maxx = max(maxx, query(rt << 1 | 1, l, r));
    return maxx;
}

int l, r;
string op;

void solve() {
    
    
    if(op[0] == 'Q') {
    
    
        cout << query(1, l, r) << endl;
    } else if(op[0] == 'U') {
    
    
        modify(1, l, l, r);
    }
}

int main() {
    
    
    IO;
#ifdef ACM_LOCAL
    freopen("input", "r", stdin);
    freopen("output", "w", stdout);
#endif
    int o = 1, cases = 0;
//    cin >> o;
    while(o --) {
    
    
        while(cin >> n >> m) {
    
    
            for (int i = 1; i <= n; ++i) cin >> a[i];
            build(1, 1, n);
            while (m--) {
    
    
                cin >> op >> l >> r;
                solve();
            }
        }
    }
    return 0;
}