holiday

 1 #include<cstdio>
 2 #include<algorithm>
 3 #include<iostream>
 4 #include<cmath>
 5 #include<cstring>
 6 #include<cctype>     
 7 using namespace std;
 8 typedef long long ll;
 9 #define enter printf("\n")
10 const int maxn = 1e5 + 5; 
11 const int INF = 0x3f3f3f3f;
12 inline ll read()
13 {
14     ll ans = 0;
15     char ch = getchar(), last = ‘ ‘;
16     while(!isdigit(ch)) {last = ch; ch = getchar();}
17     while(isdigit(ch))
18     {
19         ans = ans * 10 + ch - ‘0‘; ch = getchar();    
20     }
21     if(last == ‘-‘) ans = -ans;
22     return ans;
23 }
24 inline void write(ll x)
25 {
26     if(x < 0) {putchar(‘-‘); x = -x;}
27     if(x == 0) {putchar(‘0‘); return;}
28     int q[100], N = 0;
29     q[1] = 0;
30     while(x) {q[++N] = x % 10; x /= 10;}
31     while(N) {putchar(‘0‘ + q[N]); --N;}
32 }
33 
34 int n, l, r;
35 ll a[maxn], sum[maxn]; 
36 ll ans = -1e10;
37 
38 ll dp[maxn][30];            
39 int size[maxn];
40 void RMQ(int n)
41 {
42     for(int i = 1; i <= n; ++i) dp[i][0] = sum[i];
43     for(int j = 1; (1 << j) <= n; ++j)
44         for(int i = 1; i + (1 << j) - 1 <= n; ++i)
45             dp[i][j] = max(dp[i][j - 1], dp[i + (1 << (j - 1))][j - 1]);
46     int k = 0;
47     for(int i = 1; i <= n; ++i) 
48     {
49         if ((1 << k) <= i) k++; 
50         size[i] = k - 1;
51     }
52 }
53 ll query(int L, int R)
54 {
55     int k = size[R - L + 1];
56     return max(dp[L][k], dp[R - (1 << k) + 1][k]);
57 }
58 
59 int main()
60 {
61     freopen("holiday.in", "r", stdin);
62     freopen("holiday.out", "w", stdout);
63     n = read(); l = read(); r = read();
64     for(int i = 1; i <= n; ++i) {a[i] = read(); sum[i] = sum[i - 1] + a[i];}
65     RMQ(n);
66     for(int i = 1; i <= n; ++i)
67     {
68         int L = i + l, R = i + r;
69         if(L > n) break;
70         if(R > n) R = n;
71         ll _ans = query(L, R) - sum[i];
72         ans = max(ans, _ans);
73     }
74     write(ans); enter;
75     return 0; 
76 }