Minimal coverage  The Problem Given several segments of line (int the X axis) with coordinates [Li,Ri]. You are to choose the minimal amount of them, such they would completely cover the segment [0,M]. The Input The first line is the number of test…

题目大意:先确定一个M, 然后输入多组线段的左端和右端的端点坐标,然后让你求出来在所给的线段中能够 把[0, M] 区域完全覆盖完的最少需要的线段数,并输出这些线段的左右端点坐标. 思路分析: 线段区间的起点是0,那么找出所有区间起点小于0中的最合适的区间. 因为需要尽量少的区间,所以选择右端点更大的区间,它包含所选线段更大. 如果在所有区间中找到了解,且右端点小于M,则把找到的区间的右端点定为新的线段区间的起点. #include <iostream> #include <stdio.…

10020 Given several segments of line (int the X axis) with coordinates [Li, Ri]. You are to choose the minimalamount of them, such they would completely cover the segment [0, M].InputThe first line is the number of test cases, followed by a blank lin…

链接: http://acm.timus.ru/problem.aspx?space=1&num=1303 按照贪心的思想,每次找到覆盖要求区间左端点时,右端点最大的线段,然后把要求覆盖的区间改为这个右端点到M这个区间.依次类推下去,这样的话就只需要扫一遍就可以找去来. 要做的预备工作就是将线段按照左端点的升序排序就可以了. 它的时间复杂度就是O(n) 代码一直WA,望大神指教 #include<iostream> #include<stdio.h> #include<…

题目传送门 /* 题意:最少需要多少条线段能覆盖[0, m]的长度 贪心:首先忽略被其他线段完全覆盖的线段,因为选取更长的更优 接着就是从p=0开始,以p点为标志,选取 (node[i].l <= p && p < node[i+1].l) 详细解释:http://www.cnblogs.com/freezhan/p/3219046.html */ #include <cstdio> #include <iostream> #include <al…

链接: http://acm.timus.ru/problem.aspx?space=1&num=1303 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=26733#problem/D D - Minimal Coverage Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice UR…

Minimal coverage The Problem Given several segments of line (int the X axis) with coordinates [Li,Ri]. You are to choose the minimal amount of them, such they would completely cover the segment [0,M]. The Input The first line is the number of test ca…

题目大意:在x轴上,给一些区间,求出能把[0,m]完全覆盖的最少区间个数及该情形下的各个区间. 题目分析:简单的区间覆盖问题.可以按这样一种策略进行下去:在所有区间起点.长度有序的前提下,对于当前起点,找到可以覆盖下去的最长区间进行覆盖,并不断更新起点,直到覆盖完所有区间. 代码如下: # include<iostream> # include<cstdio> # include<vector> # include<cstring> # include<…

可以说是区间覆盖问题的例题... Note: 区间包含+排序扫描: 要求覆盖区间[s, t]; 1.把各区间按照Left从小到大排序,如果区间1的起点大于s,则无解(因为其他区间的左起点更大):否则选择起点在s的最长区间; 2.选择区间[li, ri]后,新的起点应更新为ri,并且忽略所有区间在ri之前的部分:  Minimal coverage  The Problem Given several segments of line (int the X axis) with coordinat…

Given several segments of line (int the X axis) with coordinates [Li, Ri]. You are to choose the minimal amount of them, such they would completely cover the segment [0, M].InputThe first line is the number of test cases, followed by a blank line.Eac…