题目链接:http://codeforces.com/problemset/problem/599/D 题意:定义F(n,m)为n行m列的矩阵中方阵的个数,比如3行5列的矩阵,3x3的方阵有3个.2x2的方阵有8个.1X1的方阵有15个,所以F(3,5)=3+8+15=26.现在告诉你F(a,b)=x中的x,要你求出所有满足要求的a,b,并按a递增的顺序输出. 思路:找出n行m列的矩阵中方阵数量的表达式即可,有些小细节需要注意... code: #include <iostream> #inc…

据题意: $K=\sum\limits_{i=0}^{n-1}(n-i)*(m-i)$ $K=n^2m-(n+m)\sum{i}+\sum{i^2}$ 展开化简 $m=(6k-n+n^3)/(3n^2+3n)$ 枚举n,验证整除,只做n<=m,其余反过来输出即可 #include <iostream> #include <algorithm> #include <cstdio> #include <cstdlib> #include <cstri…

D. Spongebob and Squares Spongebob is already tired trying to reason his weird actions and calculations, so he simply asked you to find all pairs of n and m, such that there are exactly x distinct squares in the table consisting of n rows and m colum…

很容易得到n × m的方块数是 然后就是个求和的问题了,枚举两者中小的那个n ≤ m. 然后就是转化成a*m + c = x了.a,m≥0,x ≥ c.最坏是n^3 ≤ x,至于中间会不会爆,测下1e18就好. #include<bits/stdc++.h> using namespace std; typedef long long ull; vector<ull> ns; vector<ull> ms; //#define LOCAL int main() { #i…

D. Spongebob and Squares time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Spongebob is already tired trying to reason his weird actions and calculations, so he simply asked you to find all…

http://codeforces.com/contest/599/problem/D 题意:给出总的方格数x,问有多少种不同尺寸的矩形满足题意,输出方案数和长宽(3,5和5,3算两种) 思路:比赛的时候gg了..其实稍微在纸上推一下.就会得到对于n,m的矩形,一共会有-n*n*n+3*n*n*m+n+3*n*m的方格.数量级是n3. 我们可以实际跑一遍.发现对于x1E18的数量级,n不会超过1442550,1E6,可以搞. 需要注意的是,一个是会爆int,所以记得用long long 另一个是…

D. Spongebob and Squares Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/599/problem/D Description Spongebob is already tired trying to reason his weird actions and calculations, so he simply asked you to find all pairs of…

D. Spongebob and Squares   Spongebob is already tired trying to reason his weird actions and calculations, so he simply asked you to find all pairs of n and m, such that there are exactly x distinct squares in the table consisting of n rows and m col…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Spongebob is already tired trying to reason his weird actions and calculations, so he simply asked you to find all pairs of n and m, such that t…

http://codeforces.com/problemset/problem/599/D 题意:给出一个数x,问你有多少个n*m的网格中有x个正方形,输出n和m的值. 思路: 易得公式为:$\sum_{i=0}^{n}(n-i)(m-i) $ 化简得:$\left [ n(n+1)-\frac{n(n+1)}{2}\right ]*m+\frac{n(n+1)(n+2)}{6}-\frac{n(n+1)}{2}*n$ 将n作为小的数,枚举n即可. #include<iostream> #i…