题目描述:
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 come in two parts: a sequence of n integer values and a non-negative integer t. We’ll not go into details, but researchers found out that a signal encodes two integer values. These can be found as the lower and upper bound of a subrange of the sequence whose absolute value of its sum is closest to t.
You are given the sequence of n integers and the non-negative target t. You are to find a non-empty range of the sequence (i.e. a continuous subsequence) and output its lower index l and its upper index u. The absolute value of the sum of the values of the sequence from the l-th to the u-th element (inclusive) must be at least as close to t as the absolute value of the sum of any other non-empty range.
Input
The input file contains several test cases. Each test case starts with two numbers n and k. Input is terminated by n=k=0. Otherwise, 1<=n<=100000 and there follow n integers with absolute values <=10000 which constitute the sequence. Then follow k queries for this sequence. Each query is a target t with 0<=t<=1000000000.
Output
For each query output 3 numbers on a line: some closest absolute sum and the lower and upper indices of some range where this absolute sum is achieved. Possible indices start with 1 and go up to n.
样例输入:
5 1
-10 -5 0 5 10
3
10 2
-9 8 -7 6 -5 4 -3 2 -1 0
5 11
15 2
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
15 100
0 0
样例输出:
5 4 4
5 2 8
9 1 1
15 1 15
15 1 15
额,怎么说,这一题样例输入的输出结果应该有多种方法,评测应该会考虑到这一点,我们就不多说了
题目大意:
给定 n 个数,与 k 个 s 值,求区间总和的绝对值最接近 s 的一个区间,并输出它的总和绝对值、左端点、右端点。
1≤n≤100000
标准的尺取法,创造尺取法需要的单调性
代码如下:
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
const int maxn=100000+10;
pair<long long,int> p[maxn];
long long a[maxn];
long long juedui(long long x)
{
if(x<0)return -x;
return x;
}
int main()
{
int n,m;
while(1)
{
scanf("%d%d",&n,&m);
if(m==0&&n==0)
{
break;
}
p[0]=make_pair(0,0);
int i,j;
long long x;
long long sum=0;
for(i=1;i<=n;i++)
{
scanf("%lld",&x);
sum+=x;
p[i]=make_pair(sum,i);
}
sort(p,p+n+1);
long long t;
while(m--)
{
scanf("%lld",&t);
long long minn=99999999999,much;
int start=0,over=1,l,r;
while(over<=n&&minn)
{
long long num=p[over].first-p[start].first;
if(juedui(num-t)<minn)
{
minn=juedui(num-t);
l=p[start].second;
r=p[over].second;
much=juedui(num);
}
if(num<t)over++;
else if(num>t)start++;
if(start==over)over++;
}
if(r<l)swap(r,l);
printf("%lld %d %d\n",much,l+1,r);
}
}
return 0;
}