codevs 1388 砍树

1388 砍树

二分

 1 #include<cstdio>
 2 using namespace std;
 3 #define maxx(a,b) (a>b?a:b)
 4 #define minn(a,b) (a>b?b:a)
 5 #define LL long long
 6 LL n,m,h[1000000+15];
 7 inline void read(LL &now)
 8 {
 9     char ch=getchar(); now=0;
10     while(ch>'9'||ch<'0') ch=getchar();
11     while(ch>='0'&&ch<='9') now=now*10+ch-'0',ch=getchar(); 
12 }
13 
14 bool check(LL x)
15 {
16     LL t=0,tot=0;
17     for(int i=1;i<=n;i++)
18         if(h[i]>x) tot+=h[i]-x;
19     if(tot>=m) return true;
20     return false;
21 }
22 
23 int main()
24 {
25     read(n); read(m);
26     LL l=0,r=0;
27     for(int i=1;i<=n;i++)
28     {
29         read(h[i]);
30         r=maxx(r,h[i]);
31         l=minn(l,h[i]);
32     }
33     while(l+1<r)
34     {
35         LL mid=(l+r)>>1;
36         if(check(mid)) l=mid+1;
37         else r=mid-1;
38     }
39     printf("%lld",l);
40     return 0;
41 }
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posted @ 2017-09-13 20:52  Alex丶Baker  阅读(100)  评论(0)  编辑  收藏  举报