题目的大意便是找到 $|T - h_i \times 6 \times 10^{-3} - A|$ 为最小值的下标并输出 $i$。
因此我们先将这个值设为 0x3f3f3f3f，即正无穷，然后每次输入进行一次比较，若比原答案更优，则将其进行更新，并记录下标。最后输出下标即可，时间复杂度为 $O(n)$。
代码如下：
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| #include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstring>
#define init(x) memset (x,0,sizeof (x))
#define ll long long
#define ull unsigned long long
#define INF 0x3f3f3f3f
using namespace std;
const int MAX = 1e5 + 5;
const int MOD = 1e9 + 7;
ll read ();
int n,t,A,ans;
double sum = INF;
int main ()
{
n = read ();t = read ();A = read ();
for (int i = 1;i <= n;++i)
{
int x;x = read ();
if (sum > abs (t - x * 0.006 - A)) ans = i,sum = abs (t - x * 0.006 - A);
}
printf ("%d\n",ans);
return 0;
}
ll read ()
{
ll s = 0;int f = 1;
char ch = getchar ();
while ((ch < '0' || ch > '9') && ch != EOF)
{
if (ch == '-') f = -1;
ch = getchar ();
}
while (ch >= '0' && ch <= '9')
{
s = s * 10 + ch - '0';
ch = getchar ();
}
return s * f;
}
|
