Excel sheet column

Signed-off-by: Leo Ma <begeekmyfriend@gmail.com>

Author: begeekmyfriend

168_excel_sheet_column_title/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test sheet_column.c

168_excel_sheet_column_title/sheet_column.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+static char *convertToTitle(int n)
+{
+    if (n <= 0) {
+        return "";
+    }
+
+    char *result = malloc(1024);
+    int len = 0;
+    do {
+        result[len++] = ((n - 1) % 26) + 'A';
+        n = (n - 1) / 26;
+    } while (n > 0);
+    result[len] = '\0';
+
+    int i, j;
+    for (i = 0, j = len - 1; i < j; i++, j--) {
+        char c = result[i];
+        result[i] = result[j];
+        result[j] = c;
+    }
+    return result;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: ./test n\n");
+        exit(-1);
+    }
+
+    printf("%s\n", convertToTitle(atoi(argv[1])));
+    return 0;
+}

171_excel_sheet_column_number/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test sheet_column.c

171_excel_sheet_column_number/sheet_column.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+static int titleToNumber(char *s)
+{
+    int n = 0;
+    while (*s != '\0') {
+        n *= 26;
+        n += *s++ - 'A' + 1;
+    }
+
+    return n;
+}
+
+int main(int argc, char **argv)
+{
+    if (argc != 2) {
+        fprintf(stderr, "Usage: ./test ABC\n");
+        exit(-1);
+    }
+
+    printf("%d\n", titleToNumber(argv[1]));
+    return 0;
+}