hdoj薛猫猫杯程序设计网络赛1003 球球大作战

Posted 2021-01-20 wangyiming

思路：

二分，check函数不是很好写。

实现：

1.

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 const ll INF = 0x3f3f3f3f3f3f3f3f;
 5 ll a[100005];
 6 int n, k;
 7 bool check(ll x)
 8 {
 9     int cnt = 0;
10     ll sum = 0;
11     for (int i = 1; i <= n; i++)
12     {
13         if (a[i] >= x) continue;
14         sum = a[i++];
15         while (i <= n && sum < x)
16         {
17             sum += a[i++]; cnt++;
18         }
19         if (i > n && sum < x) cnt++;
20         i--;
21     }
22     return cnt <= k;
23 }
24 int main()
25 {
26     int T;
27     cin >> T;
28     while (T--)
29     {
30         ll l = INF, r;
31         cin >> n >> k;
32         for (int i = 1; i <= n; i++) 
33         {
34             cin >> a[i];
35             l = min(l, a[i]);
36             r += a[i];
37         }
38         ll ans = l;
39         while (l <= r)
40         {
41             ll m = l + r >> 1;
42             if (check(m))
43             {
44                 ans = m;
45                 l = m + 1;
46             }
47             else r = m - 1;
48         }
49         cout << ans << endl;
50     }
51     return 0;
52 }

2.

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 typedef long long ll;
 4 const ll INF = 0x3f3f3f3f3f3f3f3f;
 5 ll a[100005], b[100005];
 6 int n, k;
 7 bool check(ll x)
 8 {
 9     for (int i = 1; i <= n; i++) b[i] = a[i];
10     int cnt = 0;
11     for (int i = 1; i <= n; i++)
12     {
13         if (b[i] >= x) continue;
14         b[i + 1] += b[i];
15         cnt++;
16     }
17     return cnt <= k;
18 }
19 int main()
20 {
21     int T;
22     cin >> T;
23     while (T--)
24     {
25         ll l = INF, r;
26         cin >> n >> k;
27         for (int i = 1; i <= n; i++) 
28         {
29             cin >> a[i];
30             l = min(l, a[i]);
31             r += a[i];
32         }
33         ll ans = l;
34         while (l <= r)
35         {
36             ll m = l + r >> 1;
37             if (check(m))
38             {
39                 ans = m;
40                 l = m + 1;
41             }
42             else r = m - 1;
43         }
44         cout << ans << endl;
45     }
46     return 0;
47 }