hdu 3530 Subsequence

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。。

 #include<algorithm>
 #include<iostream>
 #include<cstdlib>
 #include<cstring>
 #include<cstdio>
 #include<vector>
 #include<map>
 #include<set>
 using std::set;
 using std::map;
 using std::min;
 using std::max;
 using std::cin;
 using std::cout;
 using std::endl;
 using std::find;
 using std::sort;
 using std::pair;
 using std::vector;
 #define sz(c) (int)(c).size()
 #define all(c) (c).begin(), (c).end()
 #define iter(c) decltype((c).begin())
 #define cls(arr,val) memset(arr,val,sizeof(arr))
 #define cpresent(c, e) (find(all(c), (e)) != (c).end())
 #define rep(i, n) for (int i = 1; i <= (int)(n); i++)
 #define tr(c, i) for (iter(c) i = (c).begin(); i != (c).end(); ++i)
 #define pb(e) push_back(e)
 #define mp(a, b) make_pair(a, b)
 #define mid ((l+r)>>1)
 #define lc (root<<1)
 #define rc (root<<1|1)
 const int Max_N = ;
 const int INF = 0x3f3f3f3f;
 typedef unsigned long long ull;
 int n, m, k, tmin, tmax;
 struct SegTree {
     struct Node { int max, min; }seg[Max_N << ];
     inline void built(int root, int l, int r) {
         if (l == r) {
             scanf("%d", &seg[root].max), seg[root].min = seg[root].max;
             return;
         }
         built(lc, l, mid);
         built(rc, mid + , r);
         seg[root].max = max(seg[lc].max, seg[rc].max);
         seg[root].min = min(seg[lc].min, seg[rc].min);
     }
     inline void query(int root, int l, int r, int x, int y) {
         if (x > r || y < l) return;
         if (x <= l && y >= r) {
             tmin = min(tmin, seg[root].min);
             tmax = max(tmax, seg[root].max);
             return;
         }
         query(lc, l, mid, x, y);
         query(rc, mid + , r, x, y);
     }
     inline int query(int l, int r) {
         tmin = INF, tmax = -INF;
         query(, , n, l, r);
         return tmax - tmin;
     }
 }seg;
 int main() {
 #ifdef LOCAL
     freopen("in.txt", "r", stdin);
     freopen("out.txt", "w+", stdout);
 #endif
     int l, r, ans;
     while (~scanf("%d %d %d", &n, &m, &k)) {
         l = , ans = ;
         seg.built(, , n);
         rep(i, n) {
             r = i;
             if (l > r) continue;
             while (seg.query(l, r) > k) l++;
             if (seg.query(l, r) >= m && seg.query(l, r) <= k) ans = max(ans, r - l + );
         }
         printf("%d\n", ans);
     }
     return ;
 }