线段树模板

线段树区间更新询问区间和模板

int Case = 1, n, m;
struct {
	int l, r;
	ll lazy, val;
	int mid(){return(l+r)/2;}
	int size(){return r-l+1;}
}tr[maxn<<2];
void pushup(int rt){tr[rt].val = tr[rt<<1].val+tr[rt<<1|1].val;}
void pushdown(int rt) {
	ll &x = tr[rt].lazy;
	tr[rt<<1].lazy = tr[rt<<1|1].lazy = x;
	tr[rt<<1].val = x*tr[rt<<1].size();
	tr[rt<<1|1].val = x*tr[rt<<1|1].size();
	x = -1;
}
void build(int rt, int l, int r) {
	tr[rt].l = l; tr[rt].r = r;tr[rt].lazy = -1;tr[rt].val = 0;
	if(l == r) return;///
	int mid = tr[rt].mid();
	build(rt<<1, l, mid);
	build(rt<<1|1, mid+1, r);
	pushup(rt);
}
void update(int rt, int l, int r, ll x) {
	if(tr[rt].l == l && tr[rt].r == r) {
		tr[rt].val = x*tr[rt].size();tr[rt].lazy = x;return;
	}
	if(tr[rt].lazy!= -1) pushdown(rt);
	int mid = tr[rt].mid();
	if(r <= mid) update(rt<<1, l, r, x);
	else if(l > mid) update(rt<<1|1, l, r, x);
	else update(rt<<1, l, mid, x),update(rt<<1|1, mid+1, r, x);
	pushup(rt);
}
int query(int rt, int l, int r) {
	if(tr[rt].l == l && tr[rt].r == r) return tr[rt].val;
	if(tr[rt].lazy != -1) pushdown(rt);
	int mid = tr[rt].mid();
	if(r <= mid) return query(rt<<1, l, r);
	else if(l > mid) return query(rt<<1|1, l, r);
	else return query(rt<<1, l, mid)+query(rt<<1|1, mid+1, r);
	pushup(rt);
}

询问区间第一个大于x的数

int query(int rt, int l, int r, int x){
	if(tr[rt].mx <= x || l > r) return -1;
	if(tr[rt].l == tr[rt].r) return tr[rt].l;
	int mid = tr[rt].mid();
	if(mid >= r) return query(rt<<1, l, r, x);
	else if(mid < l) return query(rt<<1|1, l, r, x);
	else {
		int t = query(rt<<1, l, mid, x);
		if(t==-1) return query(rt<<1|1, mid+1, r, x);
		else return t;
	}
}