给定一个仅由六个整数数字组成的数组arr[] ，任务是以24 小时格式返回可以使用给定数组中的数字表示的最长时间。
注： 24 小时制的最短时间为 00:00:00，最长为 23:59:59。如果无法形成有效时间，则打印 -1。
例子：
Input: arr[] = {0, 2, 1, 9, 3, 2}
Output: 23:29:10
Explanation:
Maximum 24-Hour Format Time that can be formed using the digits of the array is 23:29:10
Input: arr[] = {6, 2, 6, 7, 5, 6}
Output: -1
处理方法：按照以下步骤解决问题：
- 创建一个 Hashmap 并将数字的频率存储在给定的数组中。
- 从最大时间 23:59:59 迭代到最小时间 00:00:00
- 每次检查所有数字是否都在 Hashmap 中。
- 打印发现上述条件成立的第一次。如果没有找到满足条件的时间，则打印“-1”。
下面是上述方法的实现：
C++
// C++ Program of the
// above approach
#include
using namespace std;
// Function to return the maximum
// possible time in 24-Hours format
// that can be represented by array elements
string largestTimeFromDigits(vector& A)
{
// Stores the frequency
// of the array elements
map mp1, mp2;
for (auto x : A) {
mp1[x]++;
}
mp2 = mp1;
// Maximum possible time
int hr = 23, m = 59, s = 59;
// Iterate to minimum possible time
while (hr >= 0) {
int h0 = hr / 10, h1 = hr % 10;
int m0 = m / 10, m1 = m % 10;
int s0 = s / 10, s1 = s % 10;
int p = 0;
vector arr{ h0, h1, m0,
m1, s0, s1 };
// Conditions to reduce the
// the time iteratively
for (auto& it : arr) {
if (mp1[it] > 0) {
mp1[it]--;
}
else {
p = 1;
}
}
// If all required digits
// are present in the Map
if (p == 0) {
string s = "";
s = to_string(h0)
+ to_string(h1);
s += ':' + to_string(m0)
+ to_string(m1);
s += ':' + to_string(s0)
+ to_string(s1);
return s;
}
// Retrieve Original Count
mp1 = mp2;
// If seconds is reduced to 0
if (s == 0) {
s = 59;
m--;
}
// If minutes is reduced to 0
else if (m < 0) {
m = 59;
hr--;
}
if (s > 0) {
s--;
}
}
return "-1";
}
// Driver Code
int main()
{
vector v = { 0, 2, 1, 9, 3, 2 };
cout << largestTimeFromDigits(v);
} Java
// Java Program of the
// above approach
import java.util.*;
class GFG{
// Function to return the maximum
// possible time in 24-Hours format
// that can be represented by array elements
static String largestTimeFromDigits(int []A)
{
// Stores the frequency
// of the array elements
HashMap mp1 = new HashMap();
HashMap mp2 = new HashMap();
for (int x : A)
{
if(mp1.containsKey(x))
mp1.put(x, mp1.get(x) + 1);
else
mp1.put(x, 1);
}
mp2 = (HashMap) mp1.clone();
// Maximum possible time
int hr = 23, m = 59, s = 59;
// Iterate to minimum
// possible time
while (hr >= 0)
{
int h0 = hr / 10, h1 = hr % 10;
int m0 = m / 10, m1 = m % 10;
int s0 = s / 10, s1 = s % 10;
int p = 0;
int []arr = {h0, h1, m0,
m1, s0, s1};
// Conditions to reduce the
// the time iteratively
for (int it : arr)
{
if (mp1.containsKey(it) &&
mp1.get(it) > 0)
{
mp1.put(it, mp1.get(it) - 1);
}
else
{
p = 1;
}
}
// If all required digits
// are present in the Map
if (p == 0)
{
String st = "";
st = String.valueOf(h0) +
String.valueOf(h1);
st += ':' + String.valueOf(m0) +
String.valueOf(m1);
st += ':' + String.valueOf(s0) +
String.valueOf(s1);
return st;
}
// Retrieve Original Count
mp1 = (HashMap) mp2.clone();
// If seconds is reduced to 0
if (s == 0)
{
s = 59;
m--;
}
// If minutes is reduced to 0
else if (m < 0)
{
m = 59;
hr--;
}
if (s > 0)
{
s--;
}
}
return "-1";
}
// Driver Code
public static void main(String[] args)
{
int []v = {0, 2, 1, 9, 3, 2};
System.out.print(largestTimeFromDigits(v));
}
}
// This code contributed by Princi Singh Python3
# Python 3 Program of the
# above approach
# Function to return the
# maximum possible time in
# 24-Hours format that can
# be represented by array elements
def largestTimeFromDigits(A):
# Stores the frequency
# of the array elements
mp1 = {}
mp2 = {}
for x in A:
mp1[x] = mp1.get(x, 0) + 1
mp2 = mp1.copy()
# Maximum possible time
hr = 23
m = 59
s = 59
# Iterate to minimum
# possible time
while(hr >= 0):
h0 = hr//10
h1 = hr % 10
m0 = m//10
m1 = m%10
s0 = s//10
s1 = s%10
p = 0
arr = [h0, h1, m0,
m1, s0, s1]
# Conditions to reduce the
# the time iteratively
for it in arr:
if (it in mp1 and
mp1.get(it) > 0):
mp1[it] = mp1.get(it) - 1
else:
p = 1
# If all required digits
# are present in the Map
if (p == 0):
s = ""
s = (str(h0) +
str(h1))
s += (':' + str(m0) +
str(m1))
s += (':' + str(s0) +
str(s1))
return s
# Retrieve Original Count
mp1 = mp2.copy()
# If seconds is
# reduced to 0
if (s == 0):
s = 59
m -= 1
# If minutes is
# reduced to 0
elif (m < 0):
m = 59
hr -= 1
if (s > 0):
s -= 1
return "-1"
# Driver Code
if __name__ == '__main__':
v = [0, 2, 1, 9, 3, 2]
print(largestTimeFromDigits(v))
# This code is contributed by ipg2016107C#
// C# Program of the
// above approach
using System;
using System.Collections.Generic;
class GFG{
// Function to return the maximum
// possible time in 24-Hours format
// that can be represented by array elements
static String largestTimeFromDigits(int []A)
{
// Stores the frequency
// of the array elements
Dictionary mp1 = new Dictionary();
Dictionary mp2 = new Dictionary();
foreach (int x in A)
{
if(mp1.ContainsKey(x))
mp1[x] = mp1[x] + 1;
else
mp1.Add(x, 1);
}
mp2 = new Dictionary(mp1);
// Maximum possible time
int hr = 23, m = 59, s = 59;
// Iterate to minimum
// possible time
while (hr >= 0)
{
int h0 = hr / 10, h1 = hr % 10;
int m0 = m / 10, m1 = m % 10;
int s0 = s / 10, s1 = s % 10;
int p = 0;
int []arr = {h0, h1, m0,
m1, s0, s1};
// Conditions to reduce the
// the time iteratively
foreach (int it in arr)
{
if (mp1.ContainsKey(it) &&
mp1[it] > 0)
{
mp1[it]= mp1[it] - 1;
}
else
{
p = 1;
}
}
// If all required digits
// are present in the Map
if (p == 0)
{
String st = "";
st = String.Join("", h0) +
String.Join("", h1);
st += ':' + String.Join("", m0) +
String.Join("", m1);
st += ':' + String.Join("", s0) +
String.Join("", s1);
return st;
}
// Retrieve Original Count
mp1 = new Dictionary(mp2);
// If seconds is reduced to 0
if (s == 0)
{
s = 59;
m--;
}
// If minutes is reduced to 0
else if (m < 0)
{
m = 59;
hr--;
}
if (s > 0)
{
s--;
}
}
return "-1";
}
// Driver Code
public static void Main(String[] args)
{
int []v = {0, 2, 1, 9, 3, 2};
Console.Write(largestTimeFromDigits(v));
}
}
// This code is contributed by shikhasingrajput 输出：
23:29:10时间复杂度： O(60*60*60)
辅助空间： O(1)