清华数据结构oj范围查询

数据结构，范围查询

#include <stdio.h>
using namespace std;
#define maxn 500000
int s[maxn], q1[maxn], q2[maxn], recordleft[maxn], recordright[maxn];
int searchleft(int*s, int n, int e)
{
	int hi = n, lo = 0, mi;
	while (lo<hi)
	{
		mi = (hi + lo) / 2;
		if (e<s[mi])hi = mi;
		else if (s[mi] <= e)lo = mi + 1;
	}
	if (lo == 0)return --lo;
	else return (s[--lo] == e) ? --lo : lo;
}
int searchright(int*s, int n, int e)
{
	int hi = n, lo = 0, mi;
	while (lo < hi)
	{
		mi = (hi + lo) / 2;
		if (e < s[mi])hi = mi;
		else if (s[mi] <= e)lo = mi + 1;
	}
	return --lo;
}
void unqiue(int*s, int&n)
{
	int*pre = &s[0], *pconst = &s[0], p;
	for (auto i = 1; i<n; i++)
	{
		if ((p = s[i]) == *pre);
		else *(++pre) = p;
	}
	n = pre - pconst + 1;
}
void merge(int*s, int lo, int mi, int hi)
{
	int*pre = new int[mi - lo];
	for (auto i = 0; i<mi - lo; i++)pre[i] = s[lo + i];
	int j = 0, lenght_pre = mi - lo;
	while (j<lenght_pre&&mi<hi)
	{
		if (pre[j]<s[mi])s[lo++] = pre[j++];
		else s[lo++] = s[mi++];
	}
	if (j == lenght_pre && mi<hi);
	else while (j<lenght_pre)s[lo++] = pre[j++];
	delete[] pre;
}
void mergesort(int*s, int lo, int hi)
{
	int mi = (lo + hi) / 2;
	if (1<hi - lo) {
		mergesort(s, lo, mi);
		mergesort(s, mi, hi);
		merge(s, lo, mi, hi);
	}
	else;
}
int main()
{
	int n, m, i = 0, j = 0;
	scanf("%d%d", &n, &m);
	if (0 <= n && n <= maxn && 0 <= m && m <= maxn)
	{
		int num = m, nn = n;
		while (n--)
		{
			scanf("%d", &s[i]);
			if(0<=s[i]&&s[i]<=10000000)i++;
			else continue;
		}
		if (nn>1)mergesort(s, 0, nn);
		if (nn>1)unqiue(s, nn);
		while (m--)
		{
			scanf("%d%d", &q1[j], &q2[j]);
			if(q1[j]<=q2[j])j++;
			else continue
				;
		}
		int l = 0, left = 0, right = 0;
		while (l++<num)
		{
			recordleft[l] = searchleft(s, nn, q1[left++]);
			recordright[l] = searchright(s, nn, q2[right++]);
			printf("%d\n", recordright[l] - recordleft[l]);
		}
	}
	else return 0;
	return 0;
}

以上是正确答案

说明，提交的时候要提交cpp文件。

如果是提交压缩包，可能会出错。

还有就是，这里的限定，其实都是要你进行判定的。（即，不是已经给好的，是要你考虑到的）

这里用到了2分查找，端点判定，归并排序，有序的唯一化这四个知识点