fd

Author: dingjikerbo

solution/src/main/java/com/inuker/solution/MoveZeroes.java

@@ -29,7 +29,7 @@ private void swap(int[] nums, int i, int j) {
     /**
      * 如果不要求保持顺序，且写的次数最少
      */
-    public int moveZeroes2(int[] nums) {
+    public void moveZeroes2(int[] nums) {
         for (int i = 0, j = nums.length - 1; j > i; ) {
             if (nums[i] != 0) {
                 i++;

solution/src/main/java/com/inuker/solution/NextPermutation.java

@@ -9,6 +9,10 @@
  */
 public class NextPermutation {
 
+    /**
+     * 思路是从右往左找到升序转降序的转折点nums[i]
+     * 然后从升序中找到一个大于nums[i-1]的最小数与i-1交换，然后对升序整体revert为降序即可
+     */
     public void nextPermutation(int[] nums) {
         int i = nums.length - 1;
 
@@ -23,34 +27,13 @@ public void nextPermutation(int[] nums) {
             return;
         }
 
-        int index = searchSwapPoint(nums, i, nums.length - 1, nums[i - 1]);
-
-        swap(nums, i - 1, index);
-        revert(nums, i, nums.length - 1);
-    }
-
-    private int searchSwapPoint(int[] nums, int left, int right, int target) {
-        while (left <= right) {
-            int mid = left + ((right - left) >> 1);
-
-            if (left == mid) {
-                if (target >= nums[right]) {
-                    return right - 1;
-                } else {
-                    return right;
-                }
-            }
-
-            if (target > nums[mid]) {
-                right = mid - 1;
-            } else if (target < nums[mid]) {
-                left = mid;
-            } else {
-                right = mid - 1;
+        for (int j = nums.length - 1; j >= i; j--) {
+            if (nums[j] > nums[i - 1]) {
+                swap(nums, j, i - 1);
+                revert(nums, i, nums.length - 1);
+                break;
             }
         }
-
-        throw new IllegalStateException("");
     }
 
     private void swap(int[] nums, int left, int right) {

test/src/main/java/com/inuker/test/main.java

@@ -1,5 +1,6 @@
 package com.inuker.test;
 
+import com.inuker.solution.NextPermutation;
 import com.inuker.solution.SearchForARange;
 import com.leetcode.library.ListNode;
 import com.leetcode.library.RandomListNode;
@@ -28,9 +29,13 @@
 public class main {
 
     public static void main(String[] args) {
-        int[] arr = new int[] {
-                0, 0, 3, 4, 5, 0, 0
+        int[] arr = new int[]{
+                2, 2, 0, 4, 3, 1
         };
+        new NextPermutation().nextPermutation(arr);
+        for (int n : arr) {
+            System.out.print(n + " ");
+        }
     }
 
 }