g3201_3300.s3267_count_almost_equal_pairs_ii.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g3201_3300.s3267_count_almost_equal_pairs_ii;
// #Hard #Array #Hash_Table #Sorting #Counting #Enumeration
// #2024_08_28_Time_353_ms_(99.78%)_Space_45.8_MB_(56.64%)
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
public class Solution {
public int countPairs(int[] nums) {
int pairs = 0;
Map counts = new HashMap<>();
Arrays.sort(nums);
for (int num : nums) {
Set newNums = new HashSet<>();
newNums.add(num);
for (int unit1 = 1, remain1 = num; remain1 > 0; unit1 *= 10, remain1 /= 10) {
int digit1 = num / unit1 % 10;
for (int unit2 = unit1 * 10, remain2 = remain1 / 10;
remain2 > 0;
unit2 *= 10, remain2 /= 10) {
int digit2 = num / unit2 % 10;
int newNum1 =
num - digit1 * unit1 - digit2 * unit2 + digit2 * unit1 + digit1 * unit2;
newNums.add(newNum1);
for (int unit3 = unit1 * 10, remain3 = remain1 / 10;
remain3 > 0;
unit3 *= 10, remain3 /= 10) {
int digit3 = newNum1 / unit3 % 10;
for (int unit4 = unit3 * 10, remain4 = remain3 / 10;
remain4 > 0;
unit4 *= 10, remain4 /= 10) {
int digit4 = newNum1 / unit4 % 10;
int newNum2 =
newNum1
- digit3 * unit3
- digit4 * unit4
+ digit4 * unit3
+ digit3 * unit4;
newNums.add(newNum2);
}
}
}
}
for (int newNum : newNums) {
pairs += counts.getOrDefault(newNum, 0);
}
counts.put(num, counts.getOrDefault(num, 0) + 1);
}
return pairs;
}
}