BZOJ 3211 花神游历各国 线段树平方开根

题目链接：

https://www.lydsy.com/JudgeOnline/problem.php?id=3211

题目大意：

思路：

由于数据范围只有1e9，一个数字x开根号次数超过logx之后均为1，所以可以暴力开根号，但是需要剪枝优化，如果子树的max小于等于1，那么直接跳过即可。否则递归到叶子节点暴力开根号。

 #include<bits/stdc++.h>
 #define IOS ios::sync_with_stdio(false);//不可再使用scanf printf
 #define Max(a, b) ((a) > (b) ? (a) : (b))//禁用于函数，会超时
 #define Min(a, b) ((a) < (b) ? (a) : (b))
 #define Mem(a) memset(a, 0, sizeof(a))
 #define Dis(x, y, x1, y1) ((x - x1) * (x - x1) + (y - y1) * (y - y1))
 #define MID(l, r) ((l) + ((r) - (l)) / 2)
 #define lson ((o)<<1)
 #define rson ((o)<<1|1)
 #define Accepted 0
 #pragma comment(linker, "/STACK:102400000,102400000")//栈外挂
 using namespace std;
 inline int read()
 {
     int x=,f=;char ch=getchar();
     while (ch<''||ch>''){if (ch=='-') f=-;ch=getchar();}
     while (ch>=''&&ch<=''){x=x*+ch-'';ch=getchar();}
     return x*f;
 }

 typedef long long ll;
 const int maxn =  + ;
 const int MOD = ;//const引用更快，宏定义也更快
 const int INF = 1e9 + ;
 const double eps = 1e-;

 ll a[maxn];
 struct node
 {
     int l, r;
     ll mmax, sum;
 }tree[maxn<<];
 void build(int o, int l, int r)
 {
     tree[o].l = l, tree[o].r = r;
     if(l == r)
     {
         tree[o].mmax = tree[o].sum = a[l];
         return;
     }
     int m = MID(l, r);
     build(lson, l, m);
     build(rson, m + , r);
     tree[o].mmax = Max(tree[lson].mmax, tree[rson].mmax);
     tree[o].sum = tree[lson].sum + tree[rson].sum;
 }
 int ql, qr;
 ll sum;
 void query(int o)
 {
     if(ql <= tree[o].l && qr >= tree[o].r)
     {
         sum += tree[o].sum;
         return;
     }
     if(ql <= tree[lson].r)query(lson);
     if(qr >= tree[rson].l)query(rson);
 }
 void update(int o)
 {
     if(tree[o].mmax <= )return;
     if(tree[o].l == tree[o].r)
     {
         tree[o].mmax = tree[o].sum = sqrt(1.0 * tree[o].mmax);
         return ;
     }
     if(ql <= tree[lson].r)update(lson);
     if(qr >= tree[rson].l)update(rson);
     tree[o].mmax = Max(tree[lson].mmax, tree[rson].mmax);
     tree[o].sum = tree[lson].sum + tree[rson].sum;
 }
 int main()
 {
     int n, m;
     scanf("%d", &n);
     for(int i = ; i <= n; i++)scanf("%d", &a[i]);
     build(, , n);
     scanf("%d", &m);
     while(m--)
     {
         int op;
         scanf("%d%d%d", &op, &ql, &qr);
         if(op == )
         {
             sum = ;
             query();
             printf("%lld\n", sum);
         }
         else
         {
             update();
         }
     }
     return Accepted;
 }