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。

 1 #include<bits/stdc++.h>
 2 #define IOS ios::sync_with_stdio(false);//不可再使用scanf printf
 3 #define Max(a, b) ((a) > (b) ? (a) : (b))//禁用于函数，会超时
 4 #define Min(a, b) ((a) < (b) ? (a) : (b))
 5 #define Mem(a) memset(a, 0, sizeof(a))
 6 #define Dis(x, y, x1, y1) ((x - x1) * (x - x1) + (y - y1) * (y - y1))
 7 #define MID(l, r) ((l) + ((r) - (l)) / 2)
 8 #define lson ((o)<<1)
 9 #define rson ((o)<<1|1)
10 #define Accepted 0
11 #pragma comment(linker, "/STACK:102400000,102400000")//栈外挂
12 using namespace std;
13 inline int read()
14 {
15     int x=0,f=1;char ch=getchar();
16     while (ch<'0'||ch>'9'){if (ch=='-') f=-1;ch=getchar();}
17     while (ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
18     return x*f;
19 }
20 
21 typedef long long ll;
22 const int maxn = 100000 + 10;
23 const int MOD = 1000000007;//const引用更快，宏定义也更快
24 const int INF = 1e9 + 7;
25 const double eps = 1e-6;
26 
27 ll a[maxn];
28 struct node
29 {
30     int l, r;
31     ll mmax, sum;
32 }tree[maxn<<2];
33 void build(int o, int l, int r)
34 {
35     tree[o].l = l, tree[o].r = r;
36     if(l == r)
37     {
38         tree[o].mmax = tree[o].sum = a[l];
39         return;
40     }
41     int m = MID(l, r);
42     build(lson, l, m);
43     build(rson, m + 1, r);
44     tree[o].mmax = Max(tree[lson].mmax, tree[rson].mmax);
45     tree[o].sum = tree[lson].sum + tree[rson].sum;
46 }
47 int ql, qr;
48 ll sum;
49 void query(int o)
50 {
51     if(ql <= tree[o].l && qr >= tree[o].r)
52     {
53         sum += tree[o].sum;
54         return;
55     }
56     if(ql <= tree[lson].r)query(lson);
57     if(qr >= tree[rson].l)query(rson);
58 }
59 void update(int o)
60 {
61     if(tree[o].mmax <= 1)return;
62     if(tree[o].l == tree[o].r)
63     {
64         tree[o].mmax = tree[o].sum = sqrt(1.0 * tree[o].mmax);
65         return ;
66     }
67     if(ql <= tree[lson].r)update(lson);
68     if(qr >= tree[rson].l)update(rson);
69     tree[o].mmax = Max(tree[lson].mmax, tree[rson].mmax);
70     tree[o].sum = tree[lson].sum + tree[rson].sum;
71 }
72 int main()
73 {
74     int n, m;
75     scanf("%d", &n);
76     for(int i = 1; i <= n; i++)scanf("%d", &a[i]);
77     build(1, 1, n);
78     scanf("%d", &m);
79     while(m--)
80     {
81         int op;
82         scanf("%d%d%d", &op, &ql, &qr);
83         if(op == 1)
84         {
85             sum = 0;
86             query(1);
87             printf("%lld\n", sum);
88         }
89         else
90         {
91             update(1);
92         }
93     }
94     return Accepted;
95 }

 

posted @ 2018-09-21 00:55  _努力努力再努力x  阅读(158)  评论(0)  编辑  收藏  举报