http://codeforces.com/contest/773/problem/A [思路] 用 (x+a)/(y+b) = p/q 来表示其核心思想,其中a 为做对的题目,b为做的题目,则有x+a = k*p,y+b = k*q.且有0<=a<=b,两式合并可得k>=x/p,k>=(y-x)/(q-p), 则如要满足两个等式,k应取其中较大的值(注意:若取得的k为小数,我们需要的是最小整数解,加1),最后注意一下特殊情况 p = 0,p = q. 最后要注意long long…

题目链接:http://codeforces.com/problemset/problem/807/C 题目大意:给你T组数据,每组有x,y,p,q四个数,x/y是你当前提交正确率,让你求出最少需要再提交几次可以达到目标正确率p/q; 解题思路:假设提交B次,正确A次,那么可以得到(x+A)/(y+B)=p/q,可以推出x+A=k*p,y+B=k*q.那么A=k*p-x,B=K*q-y; 这样我们只需要二分枚举k,判断A,B是否满足(0<=A<=B)即可. #include<iostre…

https://codeforces.com/problemset/problem/773/A 一开始二分枚举d,使得(x+d)/(y+d)>=p/q&&x/(y+d)<=p/q,错在这些数是离散的,不能由两边异号判定一定存在这个交点. 然后改成枚举d,使得y=d*q,这样就一定是倍数了.然后就是要想清楚了,找不到这样卡在中间的d,其实都是因为d不够大的原因,d够大保证是可以的除非正确率是100%. 然后就是二分的上界,按道理q的最大值是1e9,y的最大值也是1e9,他们的公倍…

You are an experienced Codeforces user. Today you found out that during your activity on Codeforces you have made y submissions, out of which x have been successful. Thus, your current success rate on Codeforces is equal to x / y. Your favorite ratio…

C. Success Rate time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are an experienced Codeforces user. Today you found out that during your activity on Codeforces you have made ysubmissio…

http://codeforces.com/problemset/problem/807/C C. Success Rate time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are an experienced Codeforces user. Today you found out that during your…

Success Rate CodeForces - 807C 给你4个数字 x y p q ,要求让你求最小的非负整数b,使得 (x+a)/(y+b)==p/q,同时a为一个整数且0<=a<=b. (0 ≤ x ≤ y ≤ 109; 0 ≤ p ≤ q ≤ 109; y > 0; q > 0) 解法: (x+a)/(y+b)==p/q; --> x+a=np; y+b=nq; --> a=np-x; b=nq-y; --> 二分n; #include <cs…

Success Rate 思路: 水题: 代码: #include <cstdio> #include <cstring> #include <iostream> #include <algorithm> using namespace std; #define ll long long inline void in(ll &now) { ; ') Cget=getchar(); ') { now=now*+Cget-'; Cget=getchar(…

C. Success Rate time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are an experienced Codeforces user. Today you found out that during your activity on Codeforces you have made y submissi…

Success Rate 题目链接 题意 给你两个分数形式的数,然后有两种变化方式 上下都+1 仅下面部分+1 让你求第一个分数变化到第二个分数的最小步数. 思路 有几种特殊情况分类讨论一下. 首先我们先把右边化为最简比. 我们可以得到方程$$\frac{(x+a)}{(y+b)} = \frac{kp}{kq}$$ \[a = k*p - x\\b = k*q - y \] 根据\(b >= a\)可求得\(k = \frac{y-x}{q-p}\)向上取整,并且要求a>=0: 代码 #in…