s0006

src/s0006_zigzag_conversion.cpp

@@ -0,0 +1,51 @@
+#include "s0006_zigzag_conversion.hpp"
+
+// 简单地找规律
+
+// n = 3
+// 0 4 8 12   2*(n-1) * col
+// 1 3 5 ...  (n-1) * col + 1
+// 2 6 10     2*(n-1) * col + (n-1)
+
+// n = 4
+// 0     6     12   2*(n-1)*col
+// 1   5 7   11     2*(n-1)*col+row, 2*(n-1)*col-row
+// 2 4   8 10       2*(n-1)*col+row, 2*(n-1)*col-row
+// 3     9          2*(n-1)*col + (n-1)
+
+string Solution::convert(string s, int numRows) {
+  string r = "";
+  int l = s.length();
+  if (l == 1 || numRows == 1) {
+    return s;
+  }
+  for (int col = 0; 2 * (numRows - 1) * col < l; col++) {
+    r += s[2 * (numRows - 1) * col];
+  }
+  if (numRows >= 3) {
+    for (int row = 1; row < numRows - 1; row++) {
+      for (int col = 0;; col++) {
+        if (col == 0) {
+          if (2 * (numRows - 1) * col + row < l) {
+          r += s[2 * (numRows - 1) * col + row];
+          }
+        } else {
+          if (2 * (numRows - 1) * col - row < l) {
+            r += s[2 * (numRows - 1) * col - row];
+          } else {
+            break;
+          }
+          if (2 * (numRows - 1) * col + row < l) {
+            r += s[2 * (numRows - 1) * col + row];
+          } else {
+            break;
+          }
+        }
+      }
+    }
+  }
+  for (int col = 0; 2 * (numRows - 1) * col + (numRows - 1) < l; col++) {
+    r += s[2 * (numRows - 1) * col + (numRows - 1)];
+  }
+  return r;
+}