Sorted binary array means all the 0s come first, then all the 1s.
Since the array is sorted, all 0s come before all 1s. Use binary search to find the first occurrence of 1, then the count of 1s is the array length minus that index. If no 1 is found, return 0.
Pro tip: Mention that binary search gives O(log n) time, which is optimal for large arrays, and handle edge cases like all 0s or all 1s explicitly. Also, clarify that you assume the array is sorted in non-decreasing order.
Confirm the array is sorted in non-decreasing order and discuss edge cases: empty array, all 0s, all 1s.
Explain that binary search can find the transition point from 0 to 1 in O(log n) time, which is more efficient than linear scan.
Perform binary search to find the index of the first 1. If the middle element is 1, search left; else search right.
If a 1 is found at index i, the count is n - i. If no 1 is found, return 0.
State time complexity O(log n) and space O(1). Walk through examples to verify correctness.
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