给定两个字符串数组,ARR1 []和ARR2 []中,任务是计数ARR2字符串的数量[],其最小的字符的频率小于最小字符的用于ARR1每个字符串的频率[]。
例子:
Input: arr1[] = {“cbd”}, arr2[] = {“zaaaz”}
Output: 1
Explanation:
The frequency of the smallest characters in “cbd” is 1 which is less than the frequency of the smallest characters in “zaaaz” which is 2.
Therefore, the total count is 1 for the string “cbd”.
Input: arr1[] = {“yyy”,”zz”}, arr2[] = {“x”,”xx”,”xxx”,”xxxx”}
Output: 1 2
Explanation:
1. The frequency of the smallest characters in “yyy” is 3 which is less than the frequency of the smallest characters in “xxxx” which is 4.
Therefore, the total count is 1 for the string “yyy”.
2. The frequency of the smallest characters in “zz” is 2 which is less than the frequency of the smallest characters in “xxx” and “xxxx” which is 3 and 4 respectively.
Therefore, the total count is 2 for the string “zz”.
方法:这个问题可以使用贪心方法来解决。以下是步骤:
- 对于数组中的每个字符串, arr2[]计算最小字符的频率并将其存储在数组中(比如freq[] )。
- 对频率数组freq[] 进行排序。
- 现在,对于数组arr1[]中的每个字符串,计算字符串中最小字符的频率(比如X )。
- 对于每个X ,使用本文讨论的方法使用二分搜索在freq[] 中找到大于 X 的元素数。
下面是上述方法的实现:
C++
// C++ program for the above approach
#include
using namespace std;
// Function to count the frequency of
// minimum character
int countMinFreq(string s)
{
// Sort the string s
sort(s.begin(), s.end());
// Return the count with smallest
// character
return count(s.begin(), s.end(), s[0]);
}
// Function to count number of frequency
// of smallest character of string arr1[]
// is less than the string in arr2[]
void countLessThan(vector& arr1,
vector& arr2)
{
// To store the frequency of smallest
// character in each string of arr2
vector freq;
// Traverse the arr2[]
for (string s : arr2) {
// Count the frequency of smallest
// character in string s
int f = countMinFreq(s);
// Append the frequency to freq[]
freq.push_back(f);
}
// Sort the frequency array
sort(freq.begin(), freq.end());
// Traverse the array arr1[]
for (string s : arr1) {
// Count the frequency of smallest
// character in string s
int f = countMinFreq(s);
// find the element greater than f
auto it = upper_bound(freq.begin(),
freq.end(), f);
// Find the count such that
// arr1[i] < arr2[j]
int cnt = freq.size()
- (it - freq.begin());
// Print the count
cout << cnt << ' ';
}
}
// Driver Code
int main()
{
vector arr1, arr2;
arr1 = { "yyy", "zz" };
arr2 = { "x", "xx", "xxx", "xxxx" };
// Function Call
countLessThan(arr1, arr2);
return 0;
}
Java
// Java program for the above approach
import java.io.*;
import java.util.*;
class GFG
{
// Function to count the frequency of
// minimum character
static int countMinFreq(String s)
{
// Sort the string s
char[] tempArray = s.toCharArray();
Arrays.sort(tempArray);
s = new String(tempArray);
// Return the count with smallest
// character
int x = 0;
for (int i = 0; i < s.length(); i++)
if (s.charAt(i) == s.charAt(0))
x++;
return x;
}
// Function to count number of frequency
// of smallest character of string arr1[]
// is less than the string in arr2[]
static void countLessThan(List arr1,
List arr2)
{
// To store the frequency of smallest
// character in each string of arr2
List freq = new ArrayList();
// Traverse the arr2[]
for (String s : arr2)
{
// Count the frequency of smallest
// character in string s
int f = countMinFreq(s);
// Append the frequency to freq[]
freq.add(f);
}
// Sort the frequency array
Collections.sort(freq);
// Traverse the array arr1[]
for (String s : arr1) {
// Count the frequency of smallest
// character in string s
int f = countMinFreq(s);
// find the element greater than f
int it = upper_bound(freq, f);
// Find the count such that
// arr1[i] < arr2[j]
int cnt = freq.size() - it;
// Print the count
System.out.print(cnt + " ");
}
}
static int upper_bound(List freq, int f)
{
int low = 0, high = freq.size() - 1;
while (low < high) {
int mid = (low + high) / 2;
if (freq.get(mid) > f)
high = mid;
else
low = mid + 1;
}
return (freq.get(low) < f) ? low++ : low;
}
// Driver Code
public static void main(String[] args)
{
List arr1, arr2;
arr1 = Arrays.asList(new String[] { "yyy", "zz" });
arr2 = Arrays.asList(
new String[] { "x", "xx", "xxx", "xxxx" });
// Function Call
countLessThan(arr1, arr2);
}
}
// This code is contributed by jithin.
Python3
# Python3 program for the above approach
from bisect import bisect_right as upper_bound
# Function to count the frequency
# of minimum character
def countMinFreq(s):
# Sort the string s
s = sorted(s)
# Return the count with smallest
# character
x = 0
for i in s:
if i == s[0]:
x += 1
return x
# Function to count number of frequency
# of smallest character of string arr1[]
# is less than the string in arr2[]
def countLessThan(arr1, arr2):
# To store the frequency of smallest
# character in each string of arr2
freq = []
# Traverse the arr2[]
for s in arr2:
# Count the frequency of smallest
# character in string s
f = countMinFreq(s)
# Append the frequency to freq[]
freq.append(f)
# Sort the frequency array
feq = sorted(freq)
# Traverse the array arr1[]
for s in arr1:
# Count the frequency of smallest
# character in string s
f = countMinFreq(s);
# find the element greater than f
it = upper_bound(freq,f)
# Find the count such that
# arr1[i] < arr2[j]
cnt = len(freq)-it
# Print the count
print(cnt, end = " ")
# Driver Code
if __name__ == '__main__':
arr1 = ["yyy", "zz"]
arr2 = [ "x", "xx", "xxx", "xxxx"]
# Function Call
countLessThan(arr1, arr2);
# This code is contributed by Mohit Kumar
Javascript
1 2
时间复杂度: O(N + M*log M) ,其中 N 和 M 分别是给定数组的长度。
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