尺取法:顾名思义就是像尺子一样一段一段去取,保存每次的选取区间的左右端点.然后一直推进 解决问题的思路: 先移动右端点 ,右端点推进的时候一般是加 然后推进左端点,左端点一般是减 poj 2566 题意:从数列中找出连续序列,使得和的绝对值与目标数之差最小 思路: 在原来的数列开头添加一个0 每次找到的区间为 [min(i,j)+1,max(i,j)] 应用尺取法的代码: while (r <=n) { int sub = pre[r].sum - pre[l].sum; while (abs(…

B - Bound Found POJ - 2566 Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration (that must be going through a defiant phase: "But I want to use feet, not meters!"). Each…

[题目链接] http://poj.org/problem?id=2566 [题目大意] 给出一个序列,求一个子段和,使得其绝对值最接近给出值, 输出这个区间的左右端点和区间和. [题解] 因为原序列的前缀和不具有单调性,难以处理, 因此我们对前缀和进行排序,同时保留前缀和的右端点做标识作用, 题目要求区段和的绝对值最接近目标,因此排序不会造成前后顺序变化造成的影响 现在题目转化为在一个有序数列中,求一个数对,使得差值最接近给出数, 利用单调性,可以尺取解决问题. [代码] #include <…

   神奇密码 题目大意:就是给你一个数组,要你找出连续的数的绝对值的和最接近t的那一串,并且要找出数组的上界和下界的下标,并显示他们的和 因为这一题的数有正有负,所以必须要先把和求出来,然后排序,然后利用a(s,t)=sum(t)-sum(s)找出目标 #include <iostream> #include <algorithm> #include <functional> using namespace std; //pair<int, int>Acc…

Bound Found Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 1445   Accepted: 487   Special Judge Description Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration…

Description Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration (that must be going through a defiant phase: "But I want to use feet, not meters!"). Each signal seems to…

Bound Found Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 4297   Accepted: 1351   Special Judge Description Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration…

Bound Found Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 4384   Accepted: 1377   Special Judge Description Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration…

传送门 参考资料: [1]:http://www.voidcn.com/article/p-huucvank-dv.html 题意: 题意就是找一个连续的子区间,使它的和的绝对值最接近target. 题解: 这题的做法是先预处理出前缀和,然后对前缀和进行排序,再用尺取法贪心的去找最合适的区间. 要注意的是尺取法时首尾指针一定不能相同,因为这时区间相减结果为0,但实际上区间为空,这是不存在的,可能会产生错误的结果. 处理时,把(0,0)这个点也放进数组一起排序,比单独判断起点为1的区间更方便. 还…

Bound Found Time Limit: 5000MS   Memory Limit: 65536K Total Submissions: 1651   Accepted: 544   Special Judge Description Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration…