171

src/171.c

@@ -0,0 +1,21 @@
+#include <math.h>
+#include <string.h>
+#include <assert.h>
+
+int titleToNumber(char* columnTitle) {
+    int colnum = 0;
+    int csize = strlen(columnTitle);
+    for (int i = 0; i < csize; i++) {
+        colnum += (columnTitle[i] - 'A' + 1) * pow(26, csize - i - 1);
+    }
+
+    return colnum;
+}
+
+int main() {
+    assert(titleToNumber("A") == 1);
+    assert(titleToNumber("AB") == 28);
+    assert(titleToNumber("ZY") == 701);
+
+    return 0;
+}