Grouped iteration in Leetcode problems

Scenario

If an array can be divided into multiple groups, and for each group, we can use the same logic to deal with them, then we can use Grouped Iteration to solve the problem.

• Outer loop will be responsible for recording the first element of the group plus update the answer.
• Inner group will be responsible for finding the last element of the group.

Note that if every group does not intersect with each other, we can use grouped iteration.

Basic Template

int n = nums.length;
int i = 0;
while (i < n){
  //implement any check to make sure this start is valid
  //...
  //record the start position
  int start = i;
  //find the last element
  while(i<n && [SOME CONDITION]){
    i++;
  }
  //update ans
  //....
  //note that i is increamented by 1 so we need to minus 1
  i-=1;
  //start to deal with next group
}

Leetcode Problems

Leetcode Problem	Rating
1446. Consecutive Characters	1165
1869. Longer Contiguous Segments of Ones than Zeros	1205
1957. Delete Characters to Make Fancy String	1358
2110. Number of Smooth Descent Periods of a Stock	1408
228. Summary Ranges
2760. Longest Even Odd Subarray With Threshold	1420
1887. Reduction Operations to Make the Array Elements Equal	1428
2038. Remove Colored Pieces if Both Neighbors are the Same Color	1468
1759. Count Number of Homogenous Substrings	1491
1578. Minimum Time to Make Rope Colorful	1574
1839. Longest Substring Of All Vowels in Order	1580