尺取法之老年康复

codeforces 1041D  Glider 题目题目：戳这里

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 const int maxn = 2e5 + 10;
 5 struct nod
 6 {
 7     ll x1;
 8     ll x2;
 9     ll cost;
10 }nu[maxn];
11 int main() {
12     int n;
13     ll h;
14     scanf("%d %lld", &n, &h);
15     for(int i = 1; i <= n; ++i)
16     {
17         scanf("%lld %lld", &nu[i].x1, &nu[i].x2);
18     }
19     nu[n + 1].x1 = 3e9;
20     for(int i = 1; i <= n; ++i)
21     {
22         nu[i].cost = nu[i + 1].x1 - nu[i].x2;
23     }
24     ll ad = 0;
25     ll sum = 0;
26     ll ans = 0;
27     int r= 0;
28     int l = 0;
29     //尺取
30     while(l <= r && r < n)
31     {
32         if(sum >= h)
33         {
34             ++l;
35             ad -= nu[l].x2 - nu[l].x1;
36             sum -= nu[l].cost;
37         }
38         else
39         {
40             ++r;
41             ad += nu[r].x2 - nu[r].x1;
42             sum += nu[r].cost;
43         }
44         ans = max(ans, ad + h);
45     }
46     printf("%lld\n", ans);
47     return 0;
48 }
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posted @ 2018-09-17 13:50  euzmin  阅读(117)  评论(0)  编辑  收藏  举报