java concise beats 100%. easy to explain and impl in 5mins. cheers!
\nimport java.util.*;\n\nclass Solution {\n    public int minDeletionSize(String[] A) {\n        int n = A.length;\n\n        int[] pos = new int[n];\n        A
```\nimport java.util.*;\n\nclass Solution {\n    public int minDeletionSize(String[] A) {\n        int n = A.length;\n\n        int[] pos = new int[n];\n        Arrays.fill(pos, -1);\n\n        int col = A[0].length();\n        boolean[] del = new boolean[col];\n\n        int res = 0;\n        for (int c = 0; c < col; ++c) {\n            for (int i = 1; i < n; ++i) {\n                if (pos[i] != -1 && !del[pos[i]]) {\n                    continue;\n                }\n\n                if (A[i].charAt(c) > A[i - 1].charAt(c)) {\n                    pos[i] = c;\n                    continue;\n                }\n\n                if (A[i].charAt(c) < A[i - 1].charAt(c)) {\n                    del[c] = true;\n                    ++res;\n                    break;\n                }\n            }\n        }\n\n        return res;\n    }\n}\n\n```
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