D - Strip

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<string>
 6 #include<queue>
 7 #include<algorithm>
 8 #include<map>
 9 #include<iomanip>
10 #include<climits>
11 #include<string.h>
12 #include<numeric>
13 #include<cmath>
14 #include<stdlib.h>
15 #include<vector>
16 #include<stack>
17 #include<set>
18 #define FOR(x, b, e)  for(int x=b;x<=(e);x++)
19 #define REP(x, n)     for(int x=0;x<(n);x++)
20 #define mp            make_pair
21 #define INF 1e7
22 #define MAXN 100010
23 #define maxn 1000010
24 #define Mod 1000007
25 #define N 1010
26 using namespace std;
27 typedef long long LL;
28 
29 set<pair<int,int> > sa,sb;
30 int dp[MAXN],a[MAXN];
31 int n, x, s, l;
32 int main()
33 {
34     cin >> n >> s >> l;
35     FOR(i, 1, n) cin >> a[i];
36     dp[0] = 0;
37     FOR(i, 1, n) {
38         //每次加入一个数字
39         sa.insert(mp(a[i],i));
40         //第i位置，若不符合题意，则删去当前位置最左端的状态、数字
41         while (sa.rbegin()->first - sa.begin()->first > s) {
42             sb.erase(mp(dp[x],x));
43             x++;
44             sa.erase(mp(a[x],x));
45         }
46         //满足要求的话，作为有效状态加入集合sb中
47         if (i >= l && sa.size() >= l && dp[i-l] >= 0)
48             sb.insert(mp(dp[i-l],i - l));
49         if (sb.empty()) 
50             dp[i] = -1;
51         else 
52             dp[i] = sb.begin()->first + 1;
53     }
54     cout << dp[n] << endl;
55     return 0;
56 }