题目:http://codeforces.com/problemset/problem/448/D 题意:给出n,m,k,即在一个n*m的二维数组中找第k大的数,第i行第j列的数的值为i*j. 思路:二分答案,每一行中找比它小的数之和(单调函数),作为check的条件来转移. #include<bits/stdc++.h> using namespace std; int n,m; long long k; bool check(long long mid) { ; ;i<=n;i++)…

目录 题目 思路 \(Code\) 题目 CF448D Multiplication Table 思路 二分答案.这个矩阵的每一排都是递增的,所以二分\(ans\),去计算有多少个数等于\(ans\),有多少个数小于\(ans\),如果小于\(ans\)的数不多于\(k-1\)个并且小于等于\(ans\)的数不少于\(k\)个,那么当前\(ans\)就是答案. Q:如何计算小于\(ans\)的数的个数? A: \[\sum_{i=1}^{n}min(\lfloor \frac{ans-1}{i}…

D. Multiplication Table time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Bizon the Champion isn't just charming, he also is very smart. While some of us were learning the multiplication tabl…

题目链接:D. Multiplication Table 题意: 给出N×M的乘法矩阵要你求在这个惩罚矩阵中第k个小的元素(1 ≤ n, m ≤ 5·10^5; 1 ≤ k ≤ n·m). 题解: n和m最大都是5e5那矩阵最大就有2e11不能够暴力,其实这里就应该想到要用二分做的,但是我做题的时候脑抽@.@想要推规律,然后就决决了.那么讲一下二分怎么做,就先简单的二分答案在(1-n*m)中二分,然后cheak函数中找所有矩阵中比所给值小的元素,个数大于等于k为成立条件.复杂度(O(n*log(…

刚做这道题根本没想到二分,最关键是没想出来怎样统计在这个矩阵中比一个数小的有几个怎么算.造成自己想了好久最后看了别人的提示才做出来.哎.好久不做题太弱了 #include<iostream> #include<stdio.h> using namespace std; int main(){ // freopen("in.txt","r",stdin); long long n,m,k; while(cin>>n>>m…

题目:https://leetcode.com/problems/kth-smallest-number-in-multiplication-table/description/ 668. Kth Smallest Number in Multiplication Table Nearly every one have used the Multiplication Table. But could you find out the k-th smallest number quickly fr…

D. Multiplication Table time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Bizon the Champion isn't just charming, he also is very smart. While some of us were learning the multiplication tabl…

 D. Multiplication Table time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Bizon the Champion isn't just charming, he also is very smart. While some of us were learning the multiplication t…

Nearly every one have used the Multiplication Table. But could you find out the k-th smallest number quickly from the multiplication table? Given the height m and the length n of a m * n Multiplication Table, and a positive integer k, you need to ret…

Bizon the Champion isn't just charming, he also is very smart. While some of us were learning the multiplication table, Bizon the Champion had fun in his own manner. Bizon the Champion painted an n × m multiplication table, where the element on the i…