题意:给出f1=x,f2=y,f(i)=f(i-1)+f(i+1),求f(n)模上10e9+7 因为 可以求出通项公式:f(i)=f(i-1)-f(i-2) 然后 f1=x; f2=y; f3=y-x; f4=-x; f5=-y; f6=-y+x; f7=x; 发现是以6为循环的 还有注意下余数为正,就每次加上一个mod再模上mod #include<iostream> #include<cstdio> #include<cstring> #include <cm…

题目链接: B. Jzzhu and Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has invented a kind of sequences, they meet the following property: You are given x and y, please calculat…

题目链接:http://codeforces.com/contest/450/problem/B 解题报告:f1 = x,f2 = y,另外有当(i >= 2) fi = fi+1 + fi-1,现在给出x和y,k,让你输出fn % (1e9+7) 对于这题我真想说细节决定一切,f的值一共只有6个,只要把f的值全部打表打出来了就可以直接得出任何一个fk的值. 但是注意x和y的范围都是小于10^9,所以当(x+y) % MOD的时候就会可能出现还是负数的情况,所以说交题之前最好测下极端的情况,因为…

//area=(n*m)/ ((x+1)*(k-x+1)) //1: x==0; //2: x=n-1 //3: x=m-1 # include <stdio.h> long long max(long long x,long long y) { return x>y? x:y; } int main() { long long n,m,k,sum,t,ans; scanf("%lld%lld%lld",&n,&m,&k); sum=n+m-2…

题目链接:http://codeforces.com/problemset/problem/450/B B. Jzzhu and Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has invented a kind of sequences, they meet the following pr…

CodeForces 450B Jzzhu and Sequences (矩阵优化) Description Jzzhu has invented a kind of sequences, they meet the following property: \[f_1=x\] \[f_2=y\] \[f_i=f_{i-1}+f_{i+1}\text {(i>2)}\] You are given x and y, please calculate fn modulo 1000000007 (10…

B. Jzzhu and Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has invented a kind of sequences, they meet the following property: You are given x and y, please calculate fn m…

题目链接:https://vjudge.net/problem/CodeForces-450B B. Jzzhu and Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has invented a kind of sequences, they meet the following proper…

A - Jzzhu and Children Time Limit:1000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Description There are n children in Jzzhu's school. Jzzhu is going to give some candies to them. Let's number all the children from 1 to n. The i-th…

B. Jzzhu and Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Jzzhu has invented a kind of sequences, they meet the following property: You are given x and y, please calculate fn m…