Problem 307. First non-zero element in each column

Julio

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For a given matrix, calculate the index of the first non-zero element in each column. Assuming a column with all elements zero is not permitted.
Example:
 in->x = [0 1 0 0;
          4 3 7 0;
          0 0 2 6;
          0 9 0 5];
 out->i = [2 1 2 3]; % row numbers

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2398 Solutions

942 Solvers

Last Solution submitted on Jan 31, 2026

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Problem Comments

2 Comments

Ned Gulley on 5 Apr 2012

I fixed the test. There was no assert statement.

Dyuman Joshi on 29 Oct 2021

Test cases have been added.

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