gold-16-16


给定一个整数数组,编写一个函数,找出索引mn,只要将索引区间[m,n]的元素排好序,整个数组就是有序的。注意:n-m尽量最小,也就是说,找出符合条件的最短序列。函数返回值为[m,n],若不存在这样的mn(例如整个数组是有序的),请返回[-1,-1]

示例:

输入: [1,2,4,7,10,11,7,12,6,7,16,18,19]
输出: [3,9]

提示:

  • 0 <= len(array) <= 1000000

//leetcode submit region begin(Prohibit modification and deletion)
class Solution {
    public int[] subSort(int[] array) {
        int[] sortedArr = Arrays.copyOf(array, array.length);
        Arrays.sort(sortedArr);
        Map<Integer, List<Integer>> indexMap = new HashMap<>();
        for (int i = 0; i < sortedArr.length; i++) {
            int value = sortedArr[i];

            if (!indexMap.containsKey(value)) {
                indexMap.put(value, new ArrayList<>());
            }
            indexMap.get(value).add(i);
        }

        int start = 0;

        while (start < array.length) {
            if (array[start] == sortedArr[start]) {
                start++;
            } else {
                break;
            }
        }

        if (start == array.length) {
            int[] result  = new int[2];
            result[0] = -1;
            result[1] = -1;
            return result;
        }

        int end = array.length - 1;
        while (end >= 0) {
            if (array[end] == sortedArr[end]) {
                end--;
            } else {
                break;
            }
        }
        int[] result  = new int[2];
        result[0] = start;
        result[1] = end;
        return result;
    }
}
//leetcode submit region end(Prohibit modification and deletion)

文章作者: 倪春恩
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