Next Permutation
Given an array of integers nums, find the next lexographically ordered permutation of nums. For example, the next permutation of arr = [1,2,3] is [1,3,2].
public void nextPermutation(int[] A) {
if(A == null || A.length <= 1) return;
int i = A.length - 2;
while(i >= 0 && A[i] >= A[i + 1]) i--; // Find 1st id i that breaks descending order
if(i >= 0) { // If not entirely descending
int j = A.length - 1; // Start from the end
while(A[j] <= A[i]) j--; // Find rightmost first larger id j
swap(A, i, j); // Switch i and j
}
reverse(A, i + 1, A.length - 1); // Reverse the descending sequence
}
public void swap(int[] A, int i, int j) {
int tmp = A[i];
A[i] = A[j];
A[j] = tmp;
}
public void reverse(int[] A, int i, int j) {
while(i < j) swap(A, i++, j--);
}Related Problems
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