feat: 串模式匹配算法（feature）

- 字符集的方式
- 字符集配合String内置方法实现.

Author: wangshan

src/dataStructure/string/StringSearch.ts

@@ -0,0 +1,62 @@
+/*
+ * @Author: wangshan
+ * @Date: 2021-11-28 16:57:18
+ * @LastEditors: wangshan
+ * @LastEditTime: 2021-11-28 22:59:24
+ * @Description: 字符串匹配（模式匹配算法）
+ */
+
+export function index(fstr: string, sstr: string, pos: number) {
+  //   debugger;
+  let i = pos;
+  let j = 1;
+  let flen = fstr.length;
+  let slen = sstr.length;
+
+  while (i <= flen && j <= slen) {
+    if (fstr[i - 1] === sstr[j - 1]) {
+      i++;
+      j++;
+    } else {
+      i = i - j + 2;
+      j = 1;
+    }
+  }
+
+  if (j > slen) {
+    return i - slen;
+  } else {
+    return 0;
+  }
+}
+
+// 算法二，查找指定位置之后的第一个匹配的子串.
+/**
+ *
+ * @param {string} target 主串
+ * @param {string} substr 子串
+ * @param {number} pos 指定位置
+ *
+ * @returns i
+ */
+
+export function Index(target: string, substr: string, pos: number) {
+  //   debugger;
+  let tlen = target.length;
+  let sublen = substr.length;
+  let i = pos;
+  if (pos > 0) {
+    while (i <= tlen - sublen + 1) {
+      // 这里循环条件的内表达式意思是，计算pos位置的范围，应当在满足字串长度时的查找范围
+      let sub = target.substr(i - 1, sublen);
+
+      if (sub === substr) {
+        return i;
+      } else {
+        i++;
+      }
+    }
+  }
+
+  return -1;
+}

src/examples/string/01.ts

@@ -0,0 +1,14 @@
+/*
+ * @Author: wangshan
+ * @Date: 2021-11-20 23:18:00
+ * @LastEditors: wangshan
+ * @LastEditTime: 2021-11-28 22:49:09
+ * @Description:串匹配算法测试-方法一
+ */
+import { index } from "../../dataStructure/string/StringSearch";
+
+let tstr = "hello wolrd";
+
+let needfindStr = "wo";
+
+console.log(index(tstr, needfindStr, 3));

src/examples/string/02.ts

@@ -0,0 +1,21 @@
+/*
+ * @Author: wangshan
+ * @Date: 2021-11-28 22:49:23
+ * @LastEditors: wangshan
+ * @LastEditTime: 2021-11-28 23:01:18
+ * @Description: 字串模式匹配算法二
+ */
+
+import { Index } from "../../dataStructure/string/StringSearch";
+
+// 测试数据
+let target = "hello world, lo";
+
+// console.log(Index(target, "wo", 3)); // 7
+// console.log(Index(target, "lo", 1)); // 4
+//空白串
+console.log(Index(target, " ", 2)); // 6
+// 测试查找不存在的子串
+console.log(Index(target, "cd", 4)); // -1
+
+// 测试成功

src/examples/string/index.ts

@@ -2,7 +2,7 @@
  * @Author: wangshan
  * @Date: 2021-06-22 00:27:02
  * @LastEditors: wangshan
- * @LastEditTime: 2021-11-20 21:09:27
+ * @LastEditTime: 2021-11-28 22:51:39
  * @Description: 入口文件
  */
 // import "@/utils/index"; // 导入自定义模块
@@ -19,4 +19,9 @@
 // import "./examples/stack/03";
 // import "./examples/stack/04";
 // import "./examples/queue/01";
-import "./examples/queue/02";
+// import "./examples/queue/02";
+
+// str
+
+// import "./examples/string/01";
+import "./examples/string/02";