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…

 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…

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…

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…

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…

http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=961 贪心,排序,对左端点贪,找最大右端点. #include <cstdio> #include <cstring> #include <algorithm> #define maxn 6000000 using namespace std; int t,…

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…

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<…

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…

题意: 数轴上有n个闭区间[ai, bi],选择尽量少的区间覆盖一条指定线段[0, m] 算法: [start, end]为已经覆盖到的区间 这是一道贪心 把各个区间先按照左端点从小到大排序,更新start为end,如果区间1在start的右端,则无解,因为其他区间更不可能覆盖到 然后在剩下的能覆盖到start的区间里面选择能覆盖到最右端的区间并更新end,然后记录在path里面.如果end的已经将m覆盖则退出循环 如果遍历完所有的区间后end依然没能覆盖到start,则无解 最后按照parh里…