【vijos 1659】 河蟹王国

线段树裸题。

注意：更新的操作一定要在修改之后再进行，否则最大值变小后无法更新。

#include <bits/stdc++.h>
using namespace std;
#define mid ((l+r)>>1)
#define lch (now<<1)
#define rch ((now<<1)+1)
#define fa (now>>1)
const int maxn = 100010;
typedef long long ll;
ll tree[maxn*5], lazy[maxn*5];
void down(int now){
	if(!lazy[now]) return;
	lazy[lch] += lazy[now];
	lazy[rch] += lazy[now];
	tree[lch] += lazy[now];
	tree[rch] += lazy[now];
	lazy[now] = 0;
}
void build(int now, int l, int r){
	if(l == r){
		scanf("%lld", &tree[now]);
		return;
	}
	build(lch, l, mid);
	build(rch, mid+1, r);
	tree[now] = max(tree[lch], tree[rch]);
}
void modify(int now, int l, int r, int pos1, int pos2, int change){
	if(l == pos1 && r == pos2){
		lazy[now] += change;
		tree[now] += change;
		return;
	}
    down(now);
	if(pos2 <= mid) modify(lch, l, mid, pos1, pos2, change);
	else if(pos1 >= mid+1) modify(rch, mid+1, r, pos1, pos2, change);
	else 	modify(lch, l, mid, pos1, mid, change), 
			modify(rch, mid+1, r, mid+1, pos2, change);
	tree[now] = max(tree[lch], tree[rch]);
}
ll que(int now, int l, int r, int pos1, int pos2){
	if(l == pos1 && r == pos2) return tree[now];
	down(now);
	if(pos2 <= mid) return que(lch, l, mid, pos1, pos2);
	else if(pos1 >= mid+1) return que(rch, mid+1, r, pos1, pos2);
	else return max(que(lch, l, mid, pos1, mid), que(rch, mid+1, r, mid+1, pos2));
	
}
int main(){
	int n, m;
	scanf("%d", &n);
	build(1, 1, n);
	scanf("%d", &m);
	for(int i = 1; i <= m; i ++){
		int a, b, c, d;
		scanf("%d", &a);
		if(a == 1){
			scanf("%d%d%d", &b, &c, &d);
			modify(1, 1, n, b, c, d);
		}else{
			scanf("%d%d", &b, &c);
			printf("%lld\n", que(1, 1, n, b, c));
		}
	}
	return 0;
}