题目连接

http://acm.hdu.edu.cn/showproblem.php?pid=3530

Subsequence

Description

There is a sequence of integers. Your task is to find the longest subsequence that satisfies the following condition: the difference between the maximum element and the minimum element of the subsequence is no smaller than m and no larger than k.

Input

There are multiple test cases.
For each test case, the first line has three integers, n, m and k. n is the length of the sequence and is in the range $[1, 100000]$. m and k are in the range $[0, 1000000]$. The second line has n integers, which are all in the range $[0, 1000000]$.
Proceed to the end of file.

Output

For each test case, print the length of the subsequence on a single line.

Sample Input

5 0 0
1 1 1 1 1
5 0 3
1 2 3 4 5

Sample Output

5
4

RMQ线段树。。

 1 #include<algorithm>
 2 #include<iostream>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<cstdio>
 6 #include<vector>
 7 #include<map>
 8 #include<set>
 9 using std::min;
10 using std::max;
11 #define sz(c) (int)(c).size()
12 #define all(c) (c).begin(), (c).end()
13 #define iter(c) decltype((c).begin())
14 #define cls(arr,val) memset(arr,val,sizeof(arr))
15 #define cpresent(c, e) (find(all(c), (e)) != (c).end())
16 #define rep(i, n) for (int i = 1; i <= (int)(n); i++)
17 #define tr(c, i) for (iter(c) i = (c).begin(); i != (c).end(); ++i)
18 #define pb(e) push_back(e)
19 #define mp(a, b) make_pair(a, b)
20 #define mid ((l+r)>>1)
21 #define lc (root<<1)
22 #define rc (root<<1|1)
23 const int Max_N = 100010;
24 const int INF = 0x3f3f3f3f;
25 typedef unsigned long long ull;
26 int n, m, k, tmin, tmax;
27 struct SegTree {
28     struct Node { int max, min; }seg[Max_N << 2];
29     inline void built(int root, int l, int r) {
30         if (l == r) {
31             scanf("%d", &seg[root].max), seg[root].min = seg[root].max;
32             return;
33         }
34         built(lc, l, mid);
35         built(rc, mid + 1, r);
36         seg[root].max = max(seg[lc].max, seg[rc].max);
37         seg[root].min = min(seg[lc].min, seg[rc].min);
38     }
39     inline void query(int root, int l, int r, int x, int y) {
40         if (x > r || y < l) return;
41         if (x <= l && y >= r) {
42             tmin = min(tmin, seg[root].min);
43             tmax = max(tmax, seg[root].max);
44             return;
45         }
46         query(lc, l, mid, x, y);
47         query(rc, mid + 1, r, x, y);
48     }
49     inline int query(int l, int r) {
50         tmin = INF, tmax = -INF;
51         query(1, 1, n, l, r);
52         return tmax - tmin;
53     }
54 }seg;
55 int main() {
56 #ifdef LOCAL
57     freopen("in.txt", "r", stdin);
58     freopen("out.txt", "w+", stdout);
59 #endif
60     int l, r, ans;
61     while (~scanf("%d %d %d", &n, &m, &k)) {
62         l = 1, ans = 0;
63         seg.built(1, 1, n);
64         rep(i, n) {
65             r = i;
66             if (l > r) continue;
67             while (seg.query(l, r) > k) l++;
68             if (seg.query(l, r) >= m && seg.query(l, r) <= k) ans = max(ans, r - l + 1);
69         }
70         printf("%d\n", ans);
71     }
72     return 0;
73 }