给定大小为N的数组，该数组最初包含所有元素为0 ，并且给出了一个Q查询，其中包含[L，R]形式的范围。任务是通过对Q查询的[L，R]范围内的每个元素加1来修改数组，然后打印包含所有唯一元素的最小长度子数组的大小。
注意：在[L，R]范围内使用基于1的索引。
例子：
Input: N = 6, Q[4][] = {{1, 3}, {4, 6}, {3, 4}, {3, 3}}
Output: 3
Explanation:
Initial array: arr[] = { 0, 0, 0, 0, 0, 0 }
Query 1: updated arr[] = { 1, 1, 1, 0, 0, 0 }.
Query 2: updated arr[] = { 1, 1, 1, 1, 1, 1 }.
Query 3: updated arr[] = { 1, 1, 2, 2, 1, 1 }.
Query 4: updated arr[] = { 1, 1, 3, 2, 1, 1 }.
The subarray { 1, 3, 2 } is minimum subarray which contains all unique elements. Thus, the answer is 3.
Input: N = 8, Q[6][] = {{1, 4}, {3, 4}, {4, 5}, {5, 5}, {7, 8}, {8, 8}}
Output: 4
Explanation:
After processing all queries, the array becomes = { 1, 1, 2, 3, 2, 0, 1, 2 }.
The subarray { 3, 2, 0, 1 } is minimum subarray which contains all unique elements. Thus, the answer is 4.
方法：这个想法是使用Prefix sum数组和“两个指针”方法解决这个问题。
- 可以通过在索引L处将数组的值增加1并在索引R + 1处将值减1来计算查询后的最终数组。
Processing of a Query:
arr[L] += 1
arr[R + 1] -= 1
- 最后，计算数组的前缀总和，以计算查询后的最终数组。然后使用“两个指针”方法来获取包含所有唯一元素的最小长度子数组。
下面是上述方法的实现：
C++
// C++ implementation to find the
// minimum size subarray containing
// all unique elements after processing
// the array for K queries of ranges
#include
using namespace std;
// Function to find minimum size subarray
// of all array elements
int subarrayLength(int A[], int R[][2],
int N, int M)
{
// Updating the array after
// processing each query
for (int i = 0; i < M; ++i) {
int l = R[i][0], r = R[i][1] + 1;
// Making it to 0-indexing
l--;
r--;
// Prefix sum array concept is used
// to obtain the count array
A[l]++;
if (r < N)
A[r]--;
}
// Iterating over the array
// to get the final array
for (int i = 1; i < N; ++i) {
A[i] += A[i - 1];
}
// Variable to get count
// of all unique elements
int count = 0;
// Hash to maintain perviously
// occured elements
unordered_set s;
// Loop to find the all
// unique elements
for (int i = 0; i < N; ++i) {
if (s.find(A[i]) == s.end())
count++;
s.insert(A[i]);
}
// array to maintain counter
// of encountered elements
vector repeat(count + 1, 0);
// variable to store answer
int ans = N;
// Using two pointers approach
int counter = 0, left = 0, right = 0;
while (right < N) {
int cur_element = A[right];
repeat[cur_element] += 1;
// Increment counter
// if occured once
if (repeat[cur_element] == 1)
++counter;
// when all unique
// elements are found
while (counter == count) {
// update answer with
// minimum size
ans = min(ans, right - left + 1);
// decrement count of
// elements from left
cur_element = A[left];
repeat[cur_element] -= 1;
++left;
// decrement counter
if (repeat[cur_element] == 0)
--counter;
}
++right;
}
return ans;
}
// Driver code
int main()
{
int N = 8, queries = 6;
int Q[][2]
= {
{ 1, 4 }, { 3, 4 }, { 4, 5 },
{ 5, 5 }, { 7, 8 }, { 8, 8 }
};
int A[N] = { 0 };
cout << subarrayLength(A, Q, N, queries);
return 0;
} Java
// Java implementation to find the
// minimum size subarray containing
// all unique elements after processing
// the array for K queries of ranges
import java.util.*;
class GFG{
// Function to find minimum size subarray
// of all array elements
static int subarrayLength(int A[], int R[][],
int N, int M)
{
// Updating the array after
// processing each query
for (int i = 0; i < M; ++i)
{
int l = R[i][0], r = R[i][1] + 1;
// Making it to 0-indexing
l--;
r--;
// Prefix sum array concept is used
// to obtain the count array
A[l]++;
if (r < N)
A[r]--;
}
// Iterating over the array
// to get the final array
for (int i = 1; i < N; ++i)
{
A[i] += A[i - 1];
}
// Variable to get count
// of all unique elements
int count = 0;
// Hash to maintain perviously
// occured elements
HashSet s = new HashSet();
// Loop to find the all
// unique elements
for (int i = 0; i < N; ++i)
{
if (!s.contains(A[i]))
count++;
s.add(A[i]);
}
// array to maintain counter
// of encountered elements
int []repeat = new int[count + 1];
// variable to store answer
int ans = N;
// Using two pointers approach
int counter = 0, left = 0, right = 0;
while (right < N)
{
int cur_element = A[right];
repeat[cur_element] += 1;
// Increment counter
// if occured once
if (repeat[cur_element] == 1)
++counter;
// when all unique
// elements are found
while (counter == count)
{
// update answer with
// minimum size
ans = Math.min(ans,
right - left + 1);
// decrement count of
// elements from left
cur_element = A[left];
repeat[cur_element] -= 1;
++left;
// decrement counter
if (repeat[cur_element] == 0)
--counter;
}
++right;
}
return ans;
}
// Driver code
public static void main(String[] args)
{
int N = 8, queries = 6;
int Q[][] = {{ 1, 4 }, { 3, 4 }, { 4, 5 },
{ 5, 5 }, { 7, 8 }, { 8, 8 }};
int A[] = new int[N];
System.out.print(subarrayLength(A, Q,
N, queries));
}
}
// This code is contributed by Rajput-Ji Python3
# Python3 implementation to find the
# minimum size subarray containing
# all unique elements after processing
# the array for K queries of ranges
# Function to find minimum size subarray
# of all array elements
def subarrayLength(A, R, N, M):
# Updating the array after
# processing each query
for i in range(M):
l = R[i][0]
r = R[i][1] + 1
# Making it to 0-indexing
l -= 1
r -= 1
# Prefix sum array concept is used
# to obtain the count array
A[l] += 1
if (r < N):
A[r] -= 1
# Iterating over the array
# to get the final array
for i in range(1 , N):
A[i] += A[i - 1]
# Variable to get count
# of all unique elements
count = 0
# Hash to maintain perviously
# occured elements
s = []
# Loop to find the all
# unique elements
for i in range(N):
if (A[i] not in s):
count += 1
s.append(A[i])
# Array to maintain counter
# of encountered elements
repeat = [0] * (count + 1)
# Variable to store answer
ans = N
# Using two pointers approach
counter, left, right = 0, 0, 0
while (right < N):
cur_element = A[right]
repeat[cur_element] += 1
# Increment counter
# if occured once
if (repeat[cur_element] == 1):
counter += 1
# When all unique
# elements are found
while (counter == count):
# update answer with
# minimum size
ans = min(ans, right - left + 1)
# Decrement count of
# elements from left
cur_element = A[left]
repeat[cur_element] -= 1
left += 1
# Decrement counter
if (repeat[cur_element] == 0):
counter -= 1
right += 1
return ans
# Driver code
if __name__ == "__main__":
N , queries = 8 , 6
Q = [ [ 1, 4 ], [ 3, 4 ], [ 4, 5 ],
[ 5, 5 ], [ 7, 8 ], [ 8, 8 ] ]
A = [0] * N
print(subarrayLength(A, Q, N, queries))
# This code is contributed by chitranayalC#
// C# implementation to find the
// minimum size subarray containing
// all unique elements after processing
// the array for K queries of ranges
using System;
using System.Collections.Generic;
class GFG{
// Function to find minimum size subarray
// of all array elements
static int subarrayLength(int []A, int [,]R,
int N, int M)
{
// Updating the array after
// processing each query
for(int i = 0; i < M; ++i)
{
int l = R[i, 0], r = R[i, 1] + 1;
// Making it to 0-indexing
l--;
r--;
// Prefix sum array concept is used
// to obtain the count array
A[l]++;
if (r < N)
A[r]--;
}
// Iterating over the array
// to get the readonly array
for(int i = 1; i < N; ++i)
{
A[i] += A[i - 1];
}
// Variable to get count
// of all unique elements
int count = 0;
// Hash to maintain perviously
// occured elements
HashSet s = new HashSet();
// Loop to find the all
// unique elements
for(int i = 0; i < N; ++i)
{
if (!s.Contains(A[i]))
count++;
s.Add(A[i]);
}
// Array to maintain counter
// of encountered elements
int []repeat = new int[count + 1];
// Variable to store answer
int ans = N;
// Using two pointers approach
int counter = 0, left = 0, right = 0;
while (right < N)
{
int cur_element = A[right];
repeat[cur_element] += 1;
// Increment counter
// if occured once
if (repeat[cur_element] == 1)
++counter;
// When all unique
// elements are found
while (counter == count)
{
// Update answer with
// minimum size
ans = Math.Min(ans,
right - left + 1);
// Decrement count of
// elements from left
cur_element = A[left];
repeat[cur_element] -= 1;
++left;
// Decrement counter
if (repeat[cur_element] == 0)
--counter;
}
++right;
}
return ans;
}
// Driver code
public static void Main(String[] args)
{
int N = 8, queries = 6;
int [,]Q = { { 1, 4 }, { 3, 4 }, { 4, 5 },
{ 5, 5 }, { 7, 8 }, { 8, 8 } };
int []A = new int[N];
Console.Write(subarrayLength(A, Q,
N, queries));
}
}
// This code is contributed by Amit Katiyar 输出：
4
时间复杂度： O(N)