cf B. Number Busters

http://codeforces.com/contest/382/problem/B

题意：给你Aa,b,w,x,c，然后每经过1秒，c=c-1;  如果b>=x,b=b-x;否则 a=a-1,b=w-(x-b);  问经过多少秒c<=a;

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define ll __int64
 5 using namespace std;
 6 
 7 ll a,b,w,x,c;
 8 
 9 int main()
10 {
11     while(scanf("%I64d%I64d%I64d%I64d%I64d",&a,&b,&w,&x,&c)!=EOF)
12     {
13            ll l=0,r=200000000000000;
14            if(c<=a)
15            {
16                printf("0\n");
17                continue;
18            }
19            b=w-b-1;
20            while(l<r)
21            {
22              ll mid=(l+r)/2;
23              ll aa=a-(b+mid*x)/w;
24              ll cc=c-mid;
25              if(cc<=aa) r=mid;
26              else l=mid+1;
27            }
28            printf("%I64d\n",l);
29     }
30 }
View Code

 

 

posted @ 2015-01-21 09:26  null1019  阅读(191)  评论(0)  编辑  收藏  举报