Shortest Unsorted Continous Subarray

“Given an integer array, you need to find one continuous subarray that if you only sort this subarray in ascending order, then the whole array will be sorted in ascending order, too.

You need to find the shortest such subarray and output its length.”

Complexity

Time: worst $O(N)$ , 4 loops are used
Space: worst $O(1)$ , to hold min and max values

References

LeetCode

Implementations

1
# TODO: Implement in Python

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function findUnsortedSubarray(nums) {
      let min = Number.MAX_VALUE;
      let max = Number.MIN_VALUE;
      let flag = false;

      for (let i = 1; i < nums.length; i++) {

          if (nums[i] < nums[i - 1]) {
              flag = true;
          }
          if (flag) {
              min = Math.min(min, nums[i]);
              
          }
      }

      console.log(`min = ${min}`);
      Tracer.delay();

      flag = false;
      for (let i = nums.length - 2; i >= 0; i--) {

          if (nums[i] > nums[i + 1]) {
              flag = true;
          }
          if (flag) {
              max = Math.max(max, nums[i]);
              
          }
      }

      console.log(`max = ${max}`);

      let l;
      let r;
      for (l = 0; l < nums.length; l++) {

          if (min < nums[l]) {
              
              break;
          }
      }
      
      for (r = nums.length - 1; r >= 0; r--) {

          if (max > nums[r]) {
              
              break;
          }
      }

      const result = r - l < 0
          ? 0
          : r - l + 1;

      console.log(`result = ${result}`);
      Tracer.delay();

      return result;
  }
  findUnsortedSubarray(D);