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;

 }