codeforces 732/D 二分

Posted 2020-08-19

给出考试时间和考试需要准备的时间，问最早考完所有科目的时间 

二分答案 NlogN

二分抄神犇的写法 感觉挺舒服的嘻嘻嘻

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 const int MAXN=1e5+5;
 4 int N,M,d[MAXN],w[MAXN],cnt[MAXN];
 5 void read(int &x){
 6     x=0;
 7     register char c=getchar();
 8     while(c<48||c>57)
 9         c=getchar();
10     for(;c>=48&&c<=57;c=getchar())
11         x=(x<<1)+(x<<3)+c-48;
12 }
13 bool check(int x)
14 {
15     memset(cnt,0,sizeof(cnt));
16     int ans = 0,val = 0;
17     for (int i=x; i>=1; i--)
18         if (d[i]&&++cnt[d[i]]==1&&w[d[i]]<i-M+ans+1)
19         {
20             ans++;
21             val+=w[d[i]];
22         }
23    return ans == M && val+M<=x;
24 }
25 int main()
26 {
27     read(N),read(M);
28     for (int i=1; i<=N; i++)
29         read(d[i]);
30     for (int i=1; i<=M; i++)
31         read(w[i]);
32     int first = 0;
33     int last = N;
34     int mid;
35     int best = -1;
36     while (first <= last)
37     {
38         mid = (first + last)/2;
39         if (check(mid))
40         {
41             last = mid-1;
42             best = mid;
43         }
44         else
45         {
46             first = mid+1;
47         }
48     }
49     printf("%d\\n",best);
50     return 0;
51 }

View Code