g0701_0800.s0775_global_and_local_inversions.Solution Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java Show documentation

Java-based LeetCode algorithm problem solutions, regularly updated

The newest version!

package g0701_0800.s0775_global_and_local_inversions;

// #Medium #Array #Math #2022_03_26_Time_1_ms_(99.74%)_Space_51.6_MB_(90.31%)

public class Solution {
    /*
     * from the above solution, we can tell that if we can find the minimum of A[j] where j >= i + 2,
     * then we could quickly return false, so two steps:
     * 1. remembering minimum
     * 2. scanning from right to left
     * 
     * Time: O(n)
     */
    public boolean isIdealPermutation(int[] nums) {
        int min = nums.length;
        for (int i = nums.length - 1; i >= 2; i--) {
            min = Math.min(min, nums[i]);
            if (nums[i - 2] > min) {
                return false;
            }
        }
        return true;
    }
}