[BZOJ2002] Bounce 弹飞绵羊(分块)

题目链接：http://www.lydsy.com/JudgeOnline/problem.php?id=2002

分块，每块中的每一个点除了自己能跳跃的距离外，还要额外维护两个值：to(i)：i跳出本块到其他块的id，st(i)：i跳出本块所需要的次数。

每次暴力更新本块内的所有值，查询的时候一直走就好。

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 #define fr first
 4 #define sc second
 5 #define cl clear
 6 #define BUG puts("here!!!")
 7 #define W(a) while(a--)
 8 #define pb(a) push_back(a)
 9 #define Rint(a) scanf("%d", &a)
10 #define Rll(a) scanf("%lld", &a)
11 #define Rs(a) scanf("%s", a)
12 #define Cin(a) cin >> a
13 #define FRead() freopen("in", "r", stdin)
14 #define FWrite() freopen("out", "w", stdout)
15 #define Rep(i, len) for(int i = 0; i < (len); i++)
16 #define For(i, a, len) for(int i = (a); i < (len); i++)
17 #define Cls(a) memset((a), 0, sizeof(a))
18 #define Clr(a, in) memset((a), (in), sizeof(a))
19 #define Full(a) memset((a), 0x7f7f7f, sizeof(a))
20 #define lrt rt << 1
21 #define rrt rt << 1 | 1
22 #define pi 3.14159265359
23 #define RT return
24 #define lowbit(in) in & (-in)
25 #define onenum(in) __builtin_popcount(in)
26 typedef long long LL;
27 typedef long double LD;
28 typedef unsigned long long ULL;
29 typedef pair<int, int> pii;
30 typedef pair<string, int> psi;
31 typedef pair<LL, LL> pll;
32 typedef map<string, int> msi;
33 typedef vector<int> vi;
34 typedef vector<LL> vl;
35 typedef vector<vl> vvl;
36 typedef vector<bool> vb;
37 
38 const int maxn = 200200;
39 int n, q, sz, cmd;
40 int st[maxn], to[maxn], k[maxn], be[maxn];
41 
42 void update(int pos, int val) {
43     k[pos] = val;
44     for(int i = pos; i >= be[pos] * sz; i--) {
45         if(i + k[i] > n - 1) {
46             st[i] = 1;
47             to[i] = -1;
48         }
49         else {
50             if(be[i] == be[i+k[i]]) {
51                 st[i] = st[i+k[i]] + 1;
52                 to[i] = to[i+k[i]];
53             }
54             else {
55                 st[i] = 1;
56                 to[i] = i + k[i];
57             }
58         }
59     }
60 }
61 
62 int query(int pos) {
63     int ret = 0;
64     while(pos != -1) {
65         ret += st[pos];
66         pos = to[pos];
67     }
68     return ret;
69 }
70 
71 signed main() {
72     // FRead();
73     int x, y;
74     while(~Rint(n)) {
75         sz = sqrt(n);
76         Cls(st); Cls(to);
77         Rep(i, n) {
78             Rint(k[i]);
79             be[i] = i / sz;
80         }
81         for(int i = n - 1; i >= 0; i--) update(i, k[i]);
82         Rint(q);
83         W(q) {
84             Rint(cmd);
85             if(cmd == 1) {
86                 Rint(x);
87                 printf("%d\n", query(x));
88             }
89             else {
90                 Rint(x); Rint(y);
91                 update(x, y);
92             }
93         }
94     }
95     RT 0;
96 }

 

posted @ 2017-06-13 19:38  Kirai  阅读(181)  评论(0)  编辑  收藏  举报