比赛-Round 2 (11 Jul)

这是 hzwer 巨佬的一场训练赛。

1. 榴莲罐头

单调队列或者纯贪心都是 O(n) ，后者空间是 O(1) 更好……

 1 #include <cstdio>
 2 #include <deque>
 3 
 4 using namespace std;
 5 
 6 typedef long long LL;
 7 
 8 const LL MOD = 100000007LL;
 9 const int _N = 1200000;
10 
11 deque<LL> Q;
12 
13 LL W[_N];
14 
15 void getnum(LL &num)
16 {
17     char tt;
18     while ((tt = getchar()) < '0' || tt > '9');
19     num = tt-'0';
20     while ((tt = getchar()) >= '0' && tt <= '9')
21         num = num*10+tt-'0';
22     return;
23 }
24 
25 int main()
26 {
27     LL N, K, i, ans;
28     getnum(N), getnum(K);
29     ans = 0;
30     for (i = 1; i <= N; ++i) {
31         LL need;
32         getnum(W[i]), getnum(need);
33         while (!Q.empty() && W[Q.back()] >= W[i])
34             Q.pop_back();
35         while (!Q.empty() && W[Q.front()]+(i-Q.front())*K >= W[i])
36             Q.pop_front();
37         Q.push_back(i);
38         ans = (ans+need*((W[Q.front()]+(i-Q.front())*K%MOD)%MOD)%MOD)%MOD;
39     }
40     printf("%lld\n", ans);//m
41     return 0;
42 }
View Code

 

 

2. 榴莲迷宫

打表找规律。a = min(n, m), b = max(n, m), ans = C(n+m+1, a) + b 。

 1 #include <cstdio> 
 2 #include <algorithm>
 3 
 4 using namespace std;
 5 
 6 typedef long long LL;
 7 
 8 const LL MOD = 1000000007LL;
 9 
10 LL Mont(LL t0, LL t1)
11 {
12     LL t = 1;
13     t0 %= MOD;
14     while (t1) {
15         if (t1 & 1) t = t*t0%MOD;
16         t1 >>= 1, t0 = t0*t0%MOD;
17     }
18     return t;
19 }
20 
21 LL C(LL dn, LL up)
22 {
23     if (dn-up < up) up = dn-up;
24     if (up < 0) return 0;
25     if (up == 0) return 1;
26     LL tmp1 = 1, tmp2 = 1;
27     for (LL i = 1; i <= up; ++i) {
28         tmp1 = tmp1*(dn-i+1)%MOD;
29         tmp2 = tmp2*i%MOD;
30     }
31     return tmp1*Mont(tmp2, MOD-2)%MOD;
32 }
33 
34 LL Lucas(LL dn, LL up)
35 {
36     if (dn-up < up) up = dn-up;
37     if (up < 0) return 0;
38     if (up == 0) return 1;
39     return Lucas(dn/MOD, up/MOD)*C(dn%MOD, up%MOD)%MOD;
40 }
41 
42 int main()
43 {
44     LL a, b;
45     scanf("%lld%lld", &a, &b);
46     printf("%lld\n", (max(a, b)%MOD+Lucas(a+b+1, min(a, b)))%MOD);
47     return 0;
48 }
View Code

 

 

3. 榴莲……（忘了）

HNOI2015 弹飞绵羊，被强制禁止使用 LCT （其实也不会写）。 

写在另一篇题解里 https://www.cnblogs.com/ghcred/p/9297934.html

posted @ 2018-07-12 09:53  derchg  阅读(126)  评论(0)  编辑  收藏  举报